---Where is mother? ---She is in the kitchen. She ___ the dinner for the party the whole afternoon.
Some students often listen to music __________ classes to refresh themselves.
— __________ when has the country been open to international trade?— 1978, I suppose.
— I think he is taking an active part in social work.—I agree with you __________.
I have offered to paint the house __________ a week’s accommodation.
I _____ you yesterday, but you weren’t in.