* * 粘膜由____________所覆盖,通过 * * 脱落细胞检查和观察宫颈粘液的变化,可以了解_________功能。
参考答案:复层鳞状上皮;卵巢
Robert is said________ abroad, but I don’t know what country he studied in.
A.to have studied
B.to study
C.to be studying
D.to be studied
钢材两种破坏现象和后果是什么?