I will not speak unless _______.
19. Which do you enjoy ______ you weekend, doing sports or watching TV?
18. She ______ stop whomever she met to tell the story about her Ah Mao.
17. ______, his idea was actually worth practicing.
16. He had already learned the news. I ______ the trouble to phone him about it.
15. The managers discussed the plan that they would like to see ______ the next year.