根据句意及首字母提示补全单。

1. The English teacher's p__           is very good.

2. I couldn't understand him because he spoke too q ____      . 

3. We were i              by his speech.

4. Don't make the same m____     again, or you will fail the exam.

5. I will never f___    __ the day when I joined the army.

硬聚氯乙烯给水管道采用（）接口可以拆卸。

A.热空气焊接

B.承插接口

C.法兰接口

D.套管式接口