If you are in any doubt as to _____ you should be doing these exercises, consult your doctor.
If you talk about it with me,please wait till I finish my work at hand.
—Did you arrive here this morning?—Yes,it was at nine o’clock we came here.
Our graduation party was success.We sang and danced until it came to end at ten o’clock.
I would like you to my birthday party,but I was busy and forgot to call you.
Professor Zhang handed out the textbooks to all the students,except who had already taken them.