用所给单词的适当形式填空。
1. Look! There are two _______ (thief) in the police station.
2. Our teacher teaches us _______ (sing) and English song.
3. We need _______ (she) to teach us Chinese.
4. He often helps me with _______ (me) English.
5. The police _______ (stand) in front of the police station.