---How can I keep healthy?---I think you ought to_________.A.do more exerciseB. doing more exerciseC. exercising more
We have lived in Beijing________two years ago.
—Could you please________my pet dog while I am away? —Sure.Don’t worry.I can look after it very well.
—Would you mind________here? —Not at all.
We don’t need to take any food.The hotel will________free meals for us.
—Could you please pass me the salt? —________