________scores of times, but Derek still couldn’t understand how to use past participle in a concrete situation.
| A．Having explained | B．Having been explained |
| C．Though it was explained | D．It was explained |
— How are you getting along with your study these days?
— I'm glad to see it is .
| A．turning up | B．turning out | C．picking up | D．picking out |
— Hello, this is Shannon. I’m afraid I won’t be able to come to your office on time.
—______ ! I’ll wait for you.
| A．That’s OK | B．No doubt | C．Cheer up | D．Hurry up |
The stamps, once ____, will be very popular with stamp-collectors.
| A．being printed | B．printing | C．to print | D．printed |
Both of these roads can lead you to the History Museum. You may take ____.
| A．neither | B．either | C．both | D．any |
–Who has broken the window in my room?
--Who else ___ it but your naughty son!
| A．could do | B．could have done | C．might do | D．must have done |