单项选择题
A.妊娠2个月以内 B.妊娠2~3个月 C.妊娠4~6个月 D.妊娠7~8个月 E.生产以后
A.10sB.30sC.40sD.50sE.60s
A.2个月以后 B.4个月以后 C.6个月以后 D.8个月以后 E.10个月以后