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
入汤剂宜先煎的药物是（）
A.人参
B.当归
C.黄芪
D.杜仲
E.石斛
His efforts to raise money for his programme were _____ because no one showed any intention to take a cent out of their pockets.[ ]
A. in place
B. in sight
C. in effect
D. in vain
