L3：

Lecture 3

第一题

What is the lecture mainly about?

A The significance of the Sun’s cycles of magnetic activity

B Consequences of gradual changes in the global climate

C Explanations for a year of very unusual weather

D An example of successfully predicting extreme weather events

第二题

What point does the professor make about the unusual weather in the northeastern United States in 1816?

A It followed an especially cold winter.

B Its clod periods alternated with exceptionally hot ones.

C It contrasted with the fairly normal weather that the rest of the world experienced that year.

D It had a severe impact on the agricultural economy of that region.

第三题

Why does the professor mention Thomas Jefferson?

A To cite a contemporary account of the weather written in 1816

B To explain the origin of a theory about the Sun’s magnetic cycles

C To give Jefferson credit for sending explorers to carefully study volcanoes

D To show how the strange weather events affected Jefferson’s presidency

第四题

The professor talks about a theory that the unusual weather in 1816 was primarily caused by the Sun’s low magnetic activity. What does he imply about the theory?

A It is no longer as widely believed as it was in the past.

B It is the theory that he and most other experts accept.

C It cannot be true, since the Sun’s magnetic activity was not low in 1816.

D It was proposed so recently that most experts have not yet been able to consider it.

第五题

According to the professor, how can volcanic eruptions affect the weather in faraway places?

A By altering the wind patterns high in the atmosphere

B By sending into the stratosphere particles that block sunlight

C By creating what is called the greenhouse effect

D By accelerating the formation of rain clouds over a large area of the world

第六题

What does the professor imply about a recent study of growth rings in trees?

A He intends to use it in future research on the effects of the Sun’s magnetism.

B He feels that it did not properly consider all the significant factors.

C He believes that its results support the volcanic theory.

D He does not have confidence in the methods used by the researchers.