能使游离黄酮和黄酮苷分离的溶剂是（）
A.乙醇
B.甲醇
C.碱水
D.乙醚
E.丙酮
参考答案：D
静脉采血首选部位是 （）
A.手背静脉
B.内踝静脉
C.肘部静脉
D.股静脉
E.头皮静脉
It was now clear that no such weapons were manufactured and none been found.
A．was found
B．were founded
C．has been found
D．have been founded
