Haze (雾霾)appears around us. Let’s do ________ helpful to protect the environment.
The students are talking about ______ holiday plans happily.
--Would you please tell me __________________?-- At 10:00 this evening.A. when will the train leaveB. when the train will leaveC. when does the train leave
Last month a new law _______in China to stop people from smoking in public places.A. is passed B. passes C. was passed
Usually, we don`t know how important something is _____ we lose it.A. or B. until C. as soon as
Father often tells me ______ too much time on computer games.A. don`t spend B. not spend C. not to spend