根据句子意思，用括号中所给的单词适当形式填空。

1. Why not               (invite) your good friend, Tom?

2. Mr. Wu is our English teacher. He teaches               (we) English.

3. He is planning to leave for Beijing on the               (nine) day of the month.

4. They                (hold) a party for the exchange students from Great Britain.

5. Teddy smiles                (happy) when he sees his mother come back from work.