用所给单词的适当形式完成句子.

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 difficult problems.

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

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

若PS—1恒电位仪刚开机工作正常过一会儿输出电压、电流慢慢增大，到限流值声光报警，则根据故障原因可采取的处理措施是（）。

A.更换比较板上的R47

B.更换机内输出保险

C.更换参比电极

D.更换IC6、IC7