输卵管绝育术的作用是（）
A.抑制排卵
B.杀灭精子
C.阻止精子与卵子相遇
D.降低宫颈黏液的黏稠度
E.降低精子存活率
参考答案：C
—I had a really good weekend at my uncle's．
—_________.
A．Oh, that's very nice of you
B．Congratulations
C．It's a pleasure
D．Oh, I'm glad to hear that
美艺公司要用160米彩绳纺织中国结，每个中国结需要用3.6米彩绳，这批彩绳最多可以编织多少个中国结？
