用括号内所给动词的适当形式填空。
1. I often see him _____ (play) basketball on the playground.   
2. Listen! I hear somebody _____ (sing) in the next room. 
3. He asks us _____ (clean) the classroom after school. 
4. The teacher made us _____ (stay) in the classroom.    
5. Why are they made _____ (stand) outside the fast food restaurant?    
6. He is a good boy. Don't let bad companions _____ (lead) him.