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问题: 单选

Years ago we didn't know this,but recent science
_______that people who don't sleep well soon
get ill.
A.has shown
B.showed
C.will show
D.is showing

解答:

比较应试一点的方法:看到recent, recently一般都是用现在完成时,表示的是过去发生的事情,对现在还有影响