按房地产按增量存量细分，通常将房地产市场划分为（）几个市场。
A.一级市场
B.二级市场
C.三级市场
D.四级市场
E.特殊市场
参考答案：A, B, C
实数m取什么值时，复数z＝m＋1＋(m－1)i是：
(1)实数；(2)虚数；(3)纯虚数．
To the parents' worry, some middle school students are ______ computer games and completely forget
their studies.[ ]
A. crazy about
B. very fond of
C. concerned for
D. serious about
