胃壁细胞可分泌的物质有（）
A.胃蛋白酶原
B.内因子
C.胃泌素
D.生长抑素
E.胃黏液
参考答案：B
--- I don’t suppose the police know who did it.
--- Well, surprisingly they do. A man has been arrested and ____ now. [ ]
A. has been questioned
B. is being questioned
C. is questioning
D. has questioned
我国基本养老保险实行的企业和职工共同缴费制度中规定，职工个人缴费的比例为本人工资的（）
A.5%
B.8%
C.18%
D.20%
