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问题 选择题
1-tan27°tan33°
tan27°+tan33°
等于（　　）
A．
3
3
B．
3
C．tan6°D．
1
tan6°
答案

因为

1-tan27°tan33°
tan27°+tan33°
=
1
tan(27°+33°)
=
1
tan60°
=
3
3
．

故选A．

选择题

(2013·吉林四校高三一诊)I really don't know how to thank you, but for your help, I ________ my lost necklace.

A．couldn't have found

B．mustn't have found

C．couldn't find

D．wouldn't find
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问答题 简答题

在斯大林之后继任苏联领导人，推行了农业改革的是谁？
查看答案