取一支硬质大试管，通过排饱和食盐水的方法先后收集半试管甲烷和半试管氯气（如下图）

根据句意，用所给动词的适当形式填空。

1. It is a fine day. The sun _________ (shine) brightly.

2. They _________ (visit) the Science Museum next Sunday.

3. Mr Brown _________ (live) in Beijing since he came to China.

4. Mr Wang _________ (teach) us English two years ago.

5. The Smiths __________ ( watch) TV at this time last night.

6. We _________ (learn) about ten English songs by the end of last term.

7. Father said that he _________ (buy) a new bike for me the next Friday.

8. Bill isn't here. He _________ (chat) with his friends in the classroom.

9. The teacher said that the moon _________ (go) round the earth.

10. The Young Pioneers will go to the zoo if it _________ (not rain) this Sunday.

Unwilling to _____his children, the old couple moved to the nursing home.

A．be burdened with

B．be burdened by

C．be a burden with

D．be a burden on

温带植物最适温20度——30度

党对公安工作领导的全面性，就是要求公安机关全面地接受党在（）的领导。

A.政治上

B.思想上

C.组织上

D.工作上

易造成变压器绕组绝缘损坏的原因有（）

A.短路故障和负荷的急剧多变使绕组受到很大的电磁力矩，而发生位移或变形

B.变压器的停送电和雷击波使绝缘因过电压而损坏

C.长时间过负荷运行，绕组产生高温损坏绝缘

D.绕组绝缘受潮，造成匝间短路