根据句意，用括号中所给单词的适当形式填空。

1. He'd like to buy a present for his sister's _______ (twelve) birthday.

2. We must pay attention to_______(tell) the differences between them.

3. David is the chairperson of the _______(student) Union.

4. We held the 29th Olympic Games _______(sucess)

5.You shouldn't worry about _______(not have ) breakfast.

6. How many _______(operate) do you perform every year?

7. I_______(stay) at home and sleep all day if there is no school tomorrow.

8. The man was badly hurt in the accident and he_______(send) to hospital immediately.