阻止精子流入宫腔的避孕方法为（）。
A.使用避孕套
B.放置宫内节育器
C.运用安全期
D.口服长效避孕药
E.口服短效避孕药
参考答案：A
___________lessons were not difficult.
A．Our few first short English
B．Our first few short English
C．Our few first English short
D．Few our first English short
脾切除术的年龄限制为
A．大于2岁
B．大于4岁
C．大于6岁
D．青春期以后
E．没有限制
