妊娠期促进 * * 发育的激素有（）.
A.雌激素
B.孕激素
C.垂体催乳激素
D.胎盘生乳素
E.HCG
参考答案：A, B, C, D
— I don’t remember having ever seen John since last week. Has he gone somewhere?
— Not really. He ______ his newly-bought apartment.
A．has decorated
B．decorated
C．has been decorating
D．was decorating
用H2SO4作再生剂的浓度是（）。
A.1%
B.2%
C.5%
D.8%
