A:体内受精
B:卵生
C:体外受精
D:变态发育
从下列方框中选出适当的答语。
A.She's sending her grandpa an e-mail.
B.I usually do my homework.
C.Because I can plant trees.
D.June.He can go swimming with his friend.
E.It's in September or October.
读经纬网示意图,回答下列问题
近些年来,我国人口增长快的主要原因是( )
有学者提出:大体而言,自宋元时期,一种新型经济的发展实际上已经在自然经济的“死水”中泛起了“微澜”。其“微澜”主要表现为