Official 12 Lec 4
答题结果:0/6
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Question 1 of 6
What is the lecture mainly about?

A.

An efficient solution to the problem of storing solar energy

B.

Energy policies in the twentieth century

C.

Reasons that solar energy is not more widely used

D.

The superiority of solar energy to oil and natural gas

我的答案:

正确答案:C

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