It __ five or ten years before the new medicine is tested on human beings.A.will takeB.tookC.takesD.has taken为什么不选A或C?说错了,那为什么不选C或D啊?

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It __ five or ten years before the new medicine is tested on human beings.A.will takeB.tookC.takesD.has taken为什么不选A或C?说错了,那为什么不选C或D啊?

It __ five or ten years before the new medicine is tested on human beings.A.will takeB.tookC.takesD.has taken为什么不选A或C?说错了,那为什么不选C或D啊?
It __ five or ten years before the new medicine is tested on human beings.
A.will take
B.took
C.takes
D.has taken
为什么不选A或C?
说错了,那为什么不选C或D啊?

It __ five or ten years before the new medicine is tested on human beings.A.will takeB.tookC.takesD.has taken为什么不选A或C?说错了,那为什么不选C或D啊?
这句话是由before引导的时间状语从句.当主句用将来时,从句总是用现在时;如果before引导的从句谓语用的是过去时,则主句动词多用过去完成时,这样以便体现动作发生的先后.由before引导的从句只有这两种情况.在这句话里,从句是现在是,主句用将来时.所以选A.


参考资料:爱问知识人

有before 出现的句子中大多采用完成时态,强调 test一直在进行

一条横线一个字母 you can ride on it.__ __ __ __ __you write with it.__ __ __ __ __ __very nice to look at.__ __ __ __ __ __ __ __ __ you see the film here.__ __ __ __ __ __say or write down numbers.__ __ __ __ __ ten times ten.__ __ __ __ __ It's ten to five. It's been five or ten years from happenning for about 50 years怎么翻译呀? It __ five or ten years before the new medicine is tested on human beings.A.will takeB.tookC.takesD.has taken为什么不选A或C?说错了,那为什么不选C或D啊? It’s __ now.let’s go home.A.fifty past four B.four past fiftyC.fifty to five D.ten to five it's ten five对ten fiv提问 It is ten twenty-five对 ten twenty-five改疑问句 It is ten past five now.对ten past five划线怎么提问 They left Fuzhou five years ago.同义句转换 :It __ five years __ they ___ Fuzhou.It __ __ five years __ they __ Fuzhou. Scientists say it may be five or ten years__it is possible to test this medicine on human patients.A:sinceB:whenC:afterD:before选哪个?为什? it is(five to ten )now (what time) It is ten twenty -five. 对这句话提问 对划线部分提问It is ten five. it's five ten now 的汉语意思 It is ten meters by five metes.这是什么语法? You should arrive on time or( ) minutes late.A .five B.ten C.five to ten D.one to five 选哪个 You should arrive in time or _minutes late.A five B.ten C five to ten D one to five (去参加生日聚 It's five ten now.We can also say it's ________________ now.我就是不知道five ten 是ten past ten还是five to ten 还是………………