受精后21~40天,胚胎最容易受致畸因素影响的部位是()
A.神经系统
B.呼吸系统
C.心脏
D.四肢
E.眼睛
参考答案:C
Even after having their grandchildren live with them for ten years, the couple felt that ________children these days was the most difficult of all family matters.
A.rising
B.raising
C.caring
D.taking care
意大利耶稣会士利玛窦来华的年份是( )
A.1482年
B.1582年
C.1682年
D.1782年