先天型心血管畸形主要发生在胚胎发育的阶段是（）
A.2～8周
B.2～3月
C.3～4月
D.2～5月
E.5～6月
参考答案：A
---When were you born?
---I was born ______ the morning of May 7th , 1995.
A. in B. on C. at
隔墙应满足的条件是轻、薄（）。
A.隔声
B.防火
C.防潮
D.稳定
E.承重
