根据句意及所给首字母写出句中所缺单词。

1. Peter's father works in a history m____.    

2. On r____days, l like listening to music and doing some reading.

3. We often think flies(苍蝇) are a____animals.

4. All the students are studying for the math e____now.

5. Did you go to summer c____on summer vacation?