干扰孕卵着床的避孕药是：
A.大剂量孕激素
B.大剂量雌激素
C.大剂量雄激素
D.大剂量前列腺素
参考答案：A
何谓胶囊化学技术？有何特点？
----I’m sure Andrew will win the first prize in the final.
----I think so. He ______for it for months.
A. is preparing B. was preparing
C. had been preparing D. has been preparing
