根据句意、首字母提示完成单词。

1. Sam's favorite subject is ________ (物理学).

2. Please ________ (翻译) these Chinese sentences into English.

3. I want to i ________ my English, so I make friends with an American girl.

4. I can't go to the movies this Saturday. I have to have my piano l_______.

5. There are many t ________ visiting Beijing every year.