注：不建议在未听懂的情况下做题
1. What is the lecture mainly about?
A. The recent discovery of an unusual tectonic plate
B. The effects of underwater riffs on plate boundaries located on land
C. The development of a new technology for studying rifts located on land
D. The process by which tectonic plates are separated
2. Why does the professor mention Iceland?
A. To support the claim that rifts occur wherever volcanoes occur
B. To point out that Iceland is located on a plate boundary
C. To give an example of a rift area that is located on land
D. To give an example of an extraordinary active rift system
3. What unexpected discovery did scientists make while studying the rift event in East Africa?
A. Rifts can widen more quickly than previously thought.
B. Some magma deposits lie closer to Earth surface than geologists realized.
C. Volcanic activity is not necessary for rift formation.
D. Volcanic activity along land rifts is different from activity along underwater rifts.
4. In the lecture the professor discusses an event that occurred along a rift in East Africa. Place the stages of this event in order.
Answer Choices
A. Molten rock flowed into the rift and widened it. |
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B. There was a brief period of inactivity. |
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C. Seismic activity began 30 kilometers south of the northern volcanoes. |
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D. There was a series of earthquakes near the northern volcanoes. |
5. According to the professor, what may eventually occur at the location of the recent rift event in East Africa?
A. Two tectonic plates will merge.
B. A deep basin will form.
C. A new fissure will open.
D. Underground earthquakes will become more frequent.
6. What does the professor imply when he says this:
A. The East Africa Rift System is much larger than previously thought.
B. “East Africa Rift System” is an obvious name for the system.
C. The East Africa Rift System is not actually a system.
D. Not all of the East Africa Rift System is located in Africa.
答案见下页