问题
单项选择题 B型题
日本血吸虫的感染期是（）
A.虫卵
B.毛蚴
C.尾蚴
D.囊蚴
E.成虫
答案
参考答案：C
搜题请搜索小程序“爱下问搜题”
日本血吸虫的感染期是（）
A.虫卵
B.毛蚴
C.尾蚴
D.囊蚴
E.成虫
参考答案：C
Everyone needs friends. We all like to close to someone. is nice to have a friend to talk, laugh, and do things with. Certainly, sometimes we need to be alone. We don't always want people . But we will feel lonely if we have a friend. No two people are just the same. Friends don't get on(相处的) well. That doesn't mean that they no longer like each other. As time passes, they will make up(言归于好) and become again. Sometimes friends move away. Then we feel very . We miss them very much, but we can them and write to them. It is likely that we would never see them again. And we can new friends. There's more good news for people who have friends. They live longer than people who don't. Why? It could be true that they are . Being happy helps you keep healthy.
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．现发现挡板某一部位出现一个小孔(小孔等可能出现在挡板的任一位置)，水经过小孔流出，求剩余液面高度X的分布函数F(x)．