We should keep ______ in the reading –room.
---How long did it ________you to solve the problem?---I _______about half an hour on it.
---Could you come back home at three o’clock?---_________. I will have a meeting at half past two and it will last two hours.
--- We will build a subway(地铁) in Taizhou before 2015.--- Wow, ________________!
--- Are you happy with your grades in the math exam?---Not at all. I can’t have ________________.
---What do you often do_______classes to relax yourselves?---We often do eye exercises, listen to music or do some running around the school.