根据汉语和首字母填空提示，写出单词，完成句子。

1. Ningxia is my h             . I love it very much.

2. It has a p_           of 20 thousand people.

3. —How far is it from your home to school?  

    —It's about 2 k            .

4. There will be heavy rain in S            China.

5. Do you know the a              to the questions.

变压器调压方式有两种，一种必须在（）情况下切换，另一种为（）切换。