Lucy had to shout on the noisy street.[]

______ do you visit your grandparents— Every two weeks.

Listen! David is talkinghappily with his mother in the next room.　— It ______ be his mother. She has gone to Yunnan to be avolunteer doctor.

Many people spoke highly of the plan at the meeting, but _______ I don’t think it is of much practical use.

Seldom______computer games ever since he entered college.[ ]