根据下列句子的意思及汉语提示，写出空缺处单词、固定短语或固定搭配的正确形式。

1. ___________ (二月) is the second month in a year.

2. How many ___________ (科目) do you have at school?

3. Tomorrow is my father's ___________ (四十九岁) birthday.

4. He likes ___________ (做运动) after class in the afternoon.

5. Shanghai is one of ___________ (大城市) in the world.

置开工时电脱盐尽可能早送电参加循环目的是（）。