井下喷射砼应进行喷水或设水幕养护，使空气湿度保持在90％左右。
参考答案：对
—What do you often do in your spare time(空闲时间)?
—I often ____________ newspapers when I am free. [ ]
A. read
B. watch
C. see
D. look
早孕时，羊膜囊与什么间的空隙为胚外体腔（）
A.羊膜
B.绒毛膜
C.底蜕膜
D.卵黄囊
E.包蜕膜
