1) Some birds ___a___ (fly) from north to south in winter.
2) Mr. So leaves his home as soon as he ___b___ (answer) the phone.
3) It's noisy next door.What ____c____ (happen) ?
4) When Dick___d___ ( finish) school, he went home at once.
5) The pupils ____e____ (not stop) writing for the whole lesson.
6) I ____f____ (wait) here until the rain stops.
7) He ____g____ ( not leave) until we give him some food.