The passage mainly aims to
A. explain why time flies when people have fun.
B. prove time slows when having fun.
C. explain brain activity when having fun.
D. illustrate why time flies.
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前寒武纪生物类型及数量丰富,化石发现。()
参考答案:错误
腕足动物和河蚌、扇贝等双壳动物属于同一个动物门。()
参考答案:错误