题目:
Calcium and Eggshells
Creating an egg requires various nutrients, among which the calcium for the shell is the most difficult to obtain. This is partly because most birds do not carry large reserves of spare calcium in their body and depend on finding sufficient extra calcium at short notice. This is not an issue if there is plenty of calcium in a bird’s ordinary diet—as there is with lammergeier birds that eat little other than bone, which is rich in calcium. For birds like swallows, whose normal diet does not include much calcium, the problem is particularly acute.
Barn swallows obtain their calcium by eating grit (sand and other small particles), but most small birds seem to rely on calcium-rich snail shells that they find on the ground during the egg-laying period. Snail searching has been seen in numerous species, including great tits, goldcrests and firecrests, and North American red-cockaded woodpeckers. The quest for calcium occurs in the evening because eggshell formation takes place mainly at night. Females go to roost (rest) with their stomachs crammed with fragments of snail shell whose calcium is extracted overnight and deposited on their eggshell.
Experiments with domestic hens found that birds provided with crushed oyster shell in the late afternoon were much less likely to produce defective eggshells than those given oyster shell only in the morning. As this example shows, and as chicken farmers are all too aware, insufficient calcium can cause havoc with breeding. Defective eggshells are only part of it; without enough calcium birds may lay shell-less eggs enclosed only by the shell membrane (a thin layer normally inside the shell) and these, of course, are doomed. With insufficient calcium some birds fail to breed at all. It is easy to imagine careless husbandry (management) resulting in a lack of calcium for poultry or cage birds, but surely wild birds can always find enough calcium?
Not true. In the 1980s, scientists Peter Drent and Jan Wijbo Woldendorp in the Netherlands discovered that great tits were struggling to find sufficient calcium to form normal eggshells. Intensive agriculture and industrialization are largely responsible for acid rain which, in turn, has resulted in the deterioration in soil quality, the loss of woodland, and a dramatic reduction in the abundance of snails. Acid rain was first noticed in the nineteenth century and occurs when pollutants like sulfur dioxide and nitrogen oxide (predominantly from coal-fired power plants) are released into the atmosphere where they dissolve in the water droplets in clouds and fall to earth as rain or snow. The result is the acidification of water bodies, but acid rain also affects soils and vegetation. It wasn’t until the 1970s that the full consequences of acid rain became apparent: killing fish, accelerating the deterioration of ancient buildings, and, by removing calcium from the soil through a process called leaching, devastating snail populations.
The lack of snails, particularly in areas of poor, sandy soils where there were few alternative sources of calcium, meant that great tits and several other small birds in the Netherlands produced eggs whose shells were typically very thin, granular, porous, fragile, and without colored spots. In calcium-poor woodlands, female great tits spent a lot of time searching for snails and, unable to find any (or enough), ate grit and sand in desperation. Some females failed to lay at all; others produced defective shells or, occasionally, eggs with no shell. The only birds that seemed to be unaffected were those whose territories overlapped with popular picnic sites where they were able to find enough fragments of chicken eggshells from the hard-boiled eggs left by untidy picnickers! Intriguingly, the pied flycatchers breeding in the same woods as the great tits had no problem producing normal eggshells. It was initially assumed that this was because the flycatchers were seasonal migrants and started egg formation soon after their arrival from Africa, where they spend winter, but it was later discovered that pied flycatchers hunt out millipedes and wood lice, whose exoskeletons (hard external body coverings) are rich in calcium.
1
Creating an egg requires various nutrients, among which the calcium for the shell is the most difficult to obtain. This is partly because most birds do not carry large reserves of spare calcium in their body and depend on finding sufficient extra calcium at short notice. This is not an issue if there is plenty of calcium in a bird’s ordinary diet—as there is with lammergeier birds that eat little other than bone, which is rich in calcium. For birds like swallows, whose normal diet does not include much calcium, the problem is particularly acute.
The word “acute” in the passage is closest in meaning to
Vocabulary Questions词汇题
Acomplex
Bsurprising
Csevere
Dcommon
2
Creating an egg requires various nutrients, among which the calcium for the shell is the most difficult to obtain. This is partly because most birds do not carry large reserves of spare calcium in their body and depend on finding sufficient extra calcium at short notice. This is not an issue if there is plenty of calcium in a bird’s ordinary diet—as there is with lammergeier birds that eat little other than bone, which is rich in calcium. For birds like swallows, whose normal diet does not include much calcium, the problem is particularly acute.
According to paragraph 1, which of the following is a reason why it may be difficult for birds to obtain enough calcium for egg creation?
Factual Information Questions事实信息题
AThey need to find calcium that has already been combined with other nutrients.
BThey compete with birds from other species for the same sources of calcium-rich food
CThey use up calcium for their bones at the time that eggs are being produced
DThey do not have enough time to find the needed amount of calcium.
3
Barn swallows obtain their calcium by eating grit (sand and other small particles), but most small birds seem to rely on calcium-rich snail shells that they find on the ground during the egg-laying period. Snail searching has been seen in numerous species, including great tits, goldcrests and firecrests, and North American red-cockaded woodpeckers. The quest for calcium occurs in the evening because eggshell formation takes place mainly at night. Females go to roost (rest) with their stomachs crammed with fragments of snail shell whose calcium is extracted overnight and deposited on their eggshell. Experiments with domestic hens found that birds provided with crushed oyster shell in the late afternoon were much less likely to produce defective eggshells than those given oyster shell only in the morning. As this example shows, and as chicken farmers are all too aware, insufficient calcium can cause havoc with breeding. Defective eggshells are only part of it; without enough calcium birds may lay shell-less eggs enclosed only by the shell membrane (a thin layer normally inside the shell) and these, of course, are doomed. With insufficient calcium some birds fail to breed at all. It is easy to imagine careless husbandry (management) resulting in a lack of calcium for poultry or cage birds, but surely wild birds can always find enough calcium?
Why does the author discuss “Experiments with domestic hens”?
Rhetorical Purpose Questions修辞目的题
ATo help explain how birds’ stomachs extract calcium from shells
BTo provide evidence that crushed oyster shells provide a better source of calcium than snail shells do
CTo show that, for successful breeding to occur, birds need to consume calcium in the hours before eggshell formation
DTo contrast eggshell production in chickens with that in wild birds like great tits, gold crests, fire crests, and woodpeckers
4
Barn swallows obtain their calcium by eating grit (sand and other small particles), but most small birds seem to rely on calcium-rich snail shells that they find on the ground during the egg-laying period. Snail searching has been seen in numerous species, including great tits, goldcrests and firecrests, and North American red-cockaded woodpeckers. The quest for calcium occurs in the evening because eggshell formation takes place mainly at night. Females go to roost (rest) with their stomachs crammed with fragments of snail shell whose calcium is extracted overnight and deposited on their eggshell. Experiments with domestic hens found that birds provided with crushed oyster shell in the late afternoon were much less likely to produce defective eggshells than those given oyster shell only in the morning. As this example shows, and as chicken farmers are all too aware, insufficient calcium can cause havoc with breeding. Defective eggshells are only part of it; without enough calcium birds may lay shell-less eggs enclosed only by the shell membrane (a thin layer normally inside the shell) and these, of course, are doomed. With insufficient calcium some birds fail to breed at all. It is easy to imagine careless husbandry (management) resulting in a lack of calcium for poultry or cage birds, but surely wild birds can always find enough calcium?
Paragraph 2 suggests that incorrect feeding of domestic birds by farmers could cause the birds to
Inference Questions推理题
Abreed at unusual times
Bbe unable to produce normal eggs
Cmake eggs that lack shell membranes
Drefuse to eat food that contains calcium
5
Not true. In the 1980s, scientists Peter Drent and Jan Wijbo Woldendorp in the Netherlands discovered that great tits were struggling to find sufficient calcium to form normal eggshells. Intensive agriculture and industrialization are largely responsible for acid rain which, in turn, has resulted in the deterioration in soil quality, the loss of woodland, and a dramatic reduction in the abundance of snails. Acid rain was first noticed in the nineteenth century and occurs when pollutants like sulfur dioxide and nitrogen oxide (predominantly from coal-fired power plants) are released into the atmosphere where they dissolve in the water droplets in clouds and fall to earth as rain or snow. The result is the acidification of water bodies, but acid rain also affects soils and vegetation. It wasn’t until the 1970s that the full consequences of acid rain became apparent: killing fish, accelerating the deterioration of ancient buildings, and, by removing calcium from the soil through a process called leaching, devastating snail populations.
All of the following are mentioned in paragraph 3 as effects of acid rain EXCEPT
Negative Factual Information Questions否定事实信息题
Aa decrease in the amount of land covered by trees
Bthe formation of sulfur dioxide and nitrogen oxide in bodies of water
Can increased rate of speed at which old buildings deteriorate
Dthe loss of an important nutrient from the soil
6
Not true. In the 1980s, scientists Peter Drent and Jan Wijbo Woldendorp in the Netherlands discovered that great tits were struggling to find sufficient calcium to form normal eggshells. Intensive agriculture and industrialization are largely responsible for acid rain which, in turn, has resulted in the deterioration in soil quality, the loss of woodland, and a dramatic reduction in the abundance of snails. Acid rain was first noticed in the nineteenth century and occurs when pollutants like sulfur dioxide and nitrogen oxide (predominantly from coal-fired power plants) are released into the atmosphere where they dissolve in the water droplets in clouds and fall to earth as rain or snow. The result is the acidification of water bodies, but acid rain also affects soils and vegetation. It wasn’t until the 1970s that the full consequences of acid rain became apparent: killing fish, accelerating the deterioration of ancient buildings, and, by removing calcium from the soil through a process called leaching, devastating snail populations.
Which of the following can be inferred from paragraph 3 about snails?
Inference Questions推理题
AThey rely on the calcium they find in the soil for their survival.
BThey significantly increased their populations after the 1970s
CThey were replaced by fish as the main source of calcium for some small birds.
DThey compete with great tits for calcium in some areas
7
The lack of snails, particularly in areas of poor, sandy soils where there were few alternative sources of calcium, meant that great tits and several other small birds in the Netherlands produced eggs whose shells were typically very thin, granular, porous, fragile, and without colored spots. In calcium-poor woodlands, female great tits spent a lot of time searching for snails and, unable to find any (or enough), ate grit and sand in desperation. Some females failed to lay at all; others produced defective shells or, occasionally, eggs with no shell. The only birds that seemed to be unaffected were those whose territories overlapped with popular picnic sites where they were able to find enough fragments of chicken eggshells from the hard-boiled eggs left by untidy picnickers! Intriguingly, the pied flycatchers breeding in the same woods as the great tits had no problem producing normal eggshells. It was initially assumed that this was because the flycatchers were seasonal migrants and started egg formation soon after their arrival from Africa, where they spend winter, but it was later discovered that pied flycatchers hunt out millipedes and wood lice, whose exoskeletons (hard external body coverings) are rich in calcium.
The word “Intriguingly” in the passage is closest in meaning to
Vocabulary Questions词汇题
ASimilarly
BClearly
CInterestingly
DGenerally
8
The lack of snails, particularly in areas of poor, sandy soils where there were few alternative sources of calcium, meant that great tits and several other small birds in the Netherlands produced eggs whose shells were typically very thin, granular, porous, fragile, and without colored spots. In calcium-poor woodlands, female great tits spent a lot of time searching for snails and, unable to find any (or enough), ate grit and sand in desperation. Some females failed to lay at all; others produced defective shells or, occasionally, eggs with no shell. The only birds that seemed to be unaffected were those whose territories overlapped with popular picnic sites where they were able to find enough fragments of chicken eggshells from the hard-boiled eggs left by untidy picnickers! Intriguingly, the pied flycatchers breeding in the same woods as the great tits had no problem producing normal eggshells. It was initially assumed that this was because the flycatchers were seasonal migrants and started egg formation soon after their arrival from Africa, where they spend winter, but it was later discovered that pied flycatchers hunt out millipedes and wood lice, whose exoskeletons (hard external body coverings) are rich in calcium.
According to paragraph 4, how were some great tits in calcium-poor woodlands able to obtain enough calcium for laying eggs?
Factual Information Questions事实信息题
AThey migrated to areas that had a greater abundance of snails.
BThey ate remains of food left by people in the birds’ territory.
CThey began to breed during a different part of the year.
DThey switched to eating the same type of food that pied flycatchers eat.
9
Not true. In the 1980s, scientists Peter Drent and Jan Wijbo Woldendorp in the Netherlands discovered that great tits were struggling to find sufficient calcium to form normal eggshells. ⬛Intensive agriculture and industrialization are largely responsible for acid rain which, in turn, has resulted in the deterioration in soil quality, the loss of woodland, and a dramatic reduction in the abundance of snails. ⬛Acid rain was first noticed in the nineteenth century and occurs when pollutants like sulfur dioxide and nitrogen oxide (predominantly from coal-fired power plants) are released into the atmosphere where they dissolve in the water droplets in clouds and fall to earth as rain or snow. ⬛The result is the acidification of water bodies, but acid rain also affects soils and vegetation.⬛ It wasn’t until the 1970s that the full consequences of acid rain became apparent: killing fish, accelerating the deterioration of ancient buildings, and, by removing calcium from the soil through a process called leaching, devastating snail populations.
Look at the four squares ⬛ that indicate where the following sentence could be added to the passage
So the possible effects of acid rain had been known for along time, but the realization of how much damage it can do is more recent.Insert Text Questions句子插入题
Where would the sentence best fit？Click on a square sentence to the passage.
10
Calcium is an important nutrient for female birds.
Prose Summary Questions概要小结题
Select 3 answers
AThe harmful effects of low levels of calcium consumption by female birds were first discovered by farmers breeding chickens.
BAcid rain can reduce the availability of calcium in soils and affect the abundance of snails, an important source of calcium for many birds.
CSoil pollution from agricultural and industrial activities has made grit harmful for birds, forcing them to look for sources of calcium other than grit.
DBefore laying eggs, most birds need to obtain significant amounts of calcium by eating calcium-rich organisms or grit.
EBecause of a lack of enough calcium in their diet, some birds are unable to lay eggs, or they produce defective shells or eggs without shells
FPicnickers sometimes leave food waste in birds’ territories in the forest, which has negatively affected the birds’ habitat and the way they obtain calcium
