开放性损伤中最容易损伤的脏器是（）。
A.胃
B.肝
C.脾
D.结肠
E.小肠
参考答案：E
The student asked her professor if he would have gone on the space ship he did know earlier.
A．if he knew
B．if he knows
C．he had known
D．had he known
什么是抽样调查？抽样调查有什么优越性？
