They were all very tired, but ________ of them would stop to take a rest.

They are quiet, aren’t they? –Yes. They are accustomed ______ at meals.

There are many people downstairs. What do you think _____?

My brother will go to America for further education this summer.— _________ Actually, we have many good universities here at home.

Mom,where is David?—He is working _____ that difficult math problem in his room.[ ]