血红蛋白种类出生时以()为主,生后迅速下降。
参考答案:HbF
男性青春期性发育的第一个信号()
A.睾丸的增大
B.首次遗精
C.身高生长突增
D.阴茎增长
E.喉结出现
This is the rule ______ you must stick.[ ]
A. to which
B. to that
C. in which
D. on which