—Is your mother still a teacher? —______.
| A．Yes, she was | B．She didn’t use to | C．No, but she used to | D．No, but she used to be |
Some of you may have finished unit one. __________ you can go on to unit two.
| A．If you may | B．If you do | C．If not | D．If so |
He observed a stranger __________ around the store at midnight.
A, wandering B. to wander
C. wander D. to be wandering
My sister, an inexperienced rider, was found sitting on the bicycle __________ to balance it.
| A．having tried | B．trying | C．to try | D．tried |
We came home after our holiday only __________ our pet dog injured.
| A．found | B．to be found | C．find | D．to find |
Start out right away，__________ you'll miss the first train.
| A．and | B．but | C．or | D．while |