抗原抗体反应分为几个阶段()。
A.2个
B.3个
C.4个
D.6个
E.7个
参考答案:A
I think the writer _______ wrote the book is very creative.
A.which
B.who
C.when
D.where
The _____ kids learn to be independent, the better it is for their future.
A.later
B.latest
C.earlier
D.earliest