听力原文：W: Kate, Let' s go for a drive somewhere this weekend.
M: That' s a good idea. Just the two of us!
What is the man doing?
A．He is making a suggestion.
B．He is making a request.
C．He is offering help.
D．He is asking for information.

若两个不相关的随机变量X和Y的标准差分别为2与4，则（3Y-2X）的方差为（）。

A.14
B.16
C.20
D.128
E.160

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商品住宅按照用途可以划分为普通商品住房、( )和别墅、高档公寓等。

A.职工家属宿舍
B．经济适用住房
C．简易住宅
D．居民房

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