People have discovered the principles of solar energy whenever fuel becomes scar

游客2024-01-13  24

问题 People have discovered the principles of solar energy whenever fuel becomes scarce and expensive but will forget them every time a new source of cheap energy is developed.

选项 A、have discovered the principles of solar energy whenever fuel becomes scarce and expensive but will forget
B、have discovered the principles of solar energy whenever fuel has become scarce and expensive but they forget
C、discovered the principles of solar energy every time fuel becomes scarce and expensive, forgetting
D、discover the principles of solar energy every time fuel became scarce and expensive, but they forget
E、discover the principles of solar energy whenever fuel becomes scarce and expensive but forget

答案 E

解析 本句的内容是表述人类的一种普遍心理现象,主从句均使用一般现在时是最佳的,A、B、C、D中,或主句或从句中的时态都不恰当,C中还用for getting分词形式,句意不通。
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