胎盘合成的激素有
A．蛋白激素
B．甾体激素
C．雌激素
D．孕激素
E．HCG
参考答案：A,B,C,D,E
I regret _____ more time with my grandma before she passed away.
A．not spending
B．not to spend
C．not spend
D．not have spent
从装满100克浓度为80%的盐水中倒出40克盐水，再倒入清水将杯倒满，这样反复三次后，杯中盐水的浓度时多少？
A．5.12%
B．12.8%
C．17.28%
D．28.8%
