不可用作地下连续墙墙体材料的是()。
A.钢筋混凝土
B.素混凝土
C.黏土
D.砂土
参考答案：D
—Why didn't Alice come to the party last night?
—I don't know ______. [ ]
A. why didn't she
B. why she didn't
C. why did she
D. why she did
证券组合的风险会随组合中证券个数的增加而降低。()
