句型转换。

1. This is a bus. (改为复数句子)

    These ______ some ______.

2. He has never been to Shanghai, ______ ______?(反意疑问句)

3. He was doing his homework at 8:00 last night. (否定句)

    He ________ ________ his homework at 8:00 last night.

4. It's very hot. (对画线提问) 

    ______ the weather ______?

5. Please take care of your sister. (同意句) 

    Please ______ ______ your sister.

在喷水减温系统中，过热汽温升高，减温水门（），减温水流量（）。