What do you think of haze(雾霾)？ —- It ____ us we all must try to do something to stop the air pollution.

Jack has made great progress recently.-________, and ________. [ ]

These trainers are ______. Theirs ______ in the locker.

You look unhappy . What’s wrong ?—I find ____ difficult ______on well with my classmates

The Greens often fly to different places ___ their holidays.[ ]