1.We should not allow teenagers to smoke. 

Teenagers should not                 to smoke.

10. Our teachers don't allow us        (stay) up.

9.We have nothing against       (run) ！

8.The boy practices      (play) tennis every day.

7.I think it's difficult for him      (become) a professional sports star.

6.The weather is too cold for us       ( play) sports outside.

5.Children's       (safe) is the most important. We should look after them very well.

4.They'd like to play games instead of       (watch) TV.

3.He needs       (spend) time with his parents.

2.Anna wants to get her ears        (pierce) .