关于产褥感染的正确描述是（）。

A.多为某一种细菌感染所致

B.感染来源多为产妇自体感染

C.产后24小时后的4~6天内，两次体温达到或超过38℃

D.产后出血不是其发生的可能诱因

E.产妇死亡的四大原因之一

请你用所给词的适当形式完成下列句子.

1. Here are some things they have learned from _____ (scientist ) studies.

2. Sunglasses are used for _____ (keep) out the sun.

3. The students are _____ (confuse) about the _____ (confuse) problem.

4. I'm considering _____ (study) in Beijing or Shanghai.

5. I felt _____ (embarrass) when everyone looked at me.