有生育力男性精子存活率应()
A.≥50%
B.≥60%
C.≥70%
D.≥75%
E.≥80%
参考答案:D
解析:精子存活率参考值:有生育能力男性精子存活率应≥75%。
Many local people in Leshan prefer to go _____ in Mount Emei for their summer holidays. [ ]
A. somewhere cold
B. cold somewhere
C. somewhere cool
D. cool somewhere
洞口地形图的主要作用是(),它的比例一般采用()。