胎儿中枢神经系统畸形常见的有()
①脑积水
②无脑儿
③脑脊膜膨出
④脊柱裂
⑤脑膜膨出
A.①②
B.①②③
C.①②③④
D.①②③④⑤
E.①②④
参考答案:D
为什么一般尽量避免使用一氧化铅和四氧化三铅?
给下列句子排序。
1. I don't know.
2. Where is my book, Danny?
3. Jenny, Where is your book?
4. Okay,okay! There it is.
5. Hmmm. I don't know.
6. Danny! Where is my book?
正确的顺序是:_______________________________