下列哪项是妊娠所必备的基本条件
A.子宫内膜与受精卵发育同步B.健康的精子C.成熟的卵子D.输卵管通畅,使精子和卵子能够结合E.以上都是
参考答案:E
生产性毒物在生产场所中最常见的存在形态
A.固体、液体
B.气体、蒸汽
C.气溶胶
D.烟、尘
E.气体、蒸汽、气溶胶
I have kept the photo I can see it easily, as it reminds me of my happy childhood in the countryside. [ ]
A. in which
B. when
C. where
D. that