根据中文提示，用词组的适当形式填空。每空一词。

1. She ______ (收到…来信) her pen friend yesterday.

2. All the athletes ______ (对…满意) with the nice service during the Beijing Olympics.

3. After the earthquake, he left for Wenchuan as a volunteer               (而不是) a tourist.

4. You______ (最好) check over your exam paper carefully before you hand it in.