子宫内膜异位症的痛经主要表现为（）
A．原发性痛经
B．继发性痛经，进行性加重
C．运动性痛经
D．偶发痛经
E．以上都不是
参考答案：B
－You've changed a lot, Eric. I remembered you ____ quiet, didn't you?
－Yes, I did. Now I'm quite outgoing. [ ]
A. used to be
B. were used to be
C. used for being
D. were used for being
阳离子交换剂失效后，一般必须用（）倍当量的再生剂去还原，才能完全恢复其交换能力。
A、0.5～1
B、1～1.5
C、1.5～2
D、0.1～0.5
