题目内容
Since the discovery of penicillin, millions of lives ________ with it.
[ ]
A.saved
B.have saved
C.are saved
D.have been saved
答案:D
提示:
提示:
|
since作介词表示“自从……以来”,谓语动词常用现在完成时,因主语是谓语动词动作的承受者,应用现在完成时的被动语态.本题句意是“青霉素的发现使数以百万计的生命得以挽救.” |
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