搜题请搜索小程序“爱下问搜题”
问题 选择题
下列命题：
①第一象限的角是锐角．
②正切函数在定义域内是增函数．
③arcsin
π
3
=
3
2
．
正确的个数是（　　）
A．0B．1C．2D．3
答案

①因为锐角的范围是0°＜θ＜90°．而第一象限角的范围是k360°＜θ＜k＜360°+90°，∈z，所以①错误．

②正切函数的单调增区间为(-

π
2
+kπ，
π
2
+kπ)，k∈Z，但在整个定义域上，正切函数不单调，所以②错误．

③根据反三角函数的定义可知，函数y=arcsinx的定义域为（-1，1）．因为

π
3
＞1，所以③错误．

故正确的个数是0个．

故选A．

听力题

动词填空：用括号内所给动词的适当形式填空，并将答案写在答题卡标有题号的横线处（本大题共8小题，每小题1分，共8分）

小题1:There is a boy       (stand) on the beach wondering if his father will come back with his fishing boat.

小题2:You          (invite)to that BBQ party, Why didn’t you go?

小题3:—It’s time to do your homework, Jack.

—Yes, Mum. I’ll turn off the TV as soon as the programme        .(end)

小题4:The teacher let his students make a survey ______(find) out your group's favourite activity.

小题5:—Where were you doing when the rainstorm came, Jerry?

—I         (read) in the library.

小题6:They         (allow)to do the experiment if they have done all the preparation.

小题7:China        (send) search planes and used 21 satellites to hunt for MH370 already.

小题8:－Did Liu Ying and Liu Yang come to your birthday party, Tina?

－Of course. I         (invite) them many times.
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单项选择题

常用的变量液压马达有：（）.

A.双速

B.三速

C.无级调速

D.A＋B＋C
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