At the Copenhagen conference, all the countries were called on to do all they could to control greenhouse gas emissions ______ it was too late.
Do you have anything is important to tell me?
20 . They have made_______a rule________in the room.
19. I wondered_____that made him so upset.
18. The stories of rescuing trapped strangers in the earthquake highlight the huge efforts_______by Haitians themselves, as well as aid workers from around the world.
15. With the reform of educational system, the teachers_____school I worked before have greatly changed their way of teaching.