All the photographs in this book, _______ stated otherwise, date from the 1970s.
| A．until | B．once | C．if | D．unless |
I don’t think it is ______taking the trouble to explain the question to him.
| A．worth | B．worthy |
| C．worth of | D．worthwhile |
It is impossible to ________one’s goal without working hard.
| A．achieve | B．get | C．arrive | D．make |
A poet and artist ______ coming to speak to us about Chinese literature and painting tomorrow afternoon.
| A．is | B．are | C．was | D．were |
The president spoke at the business meeting for nearly an hour without ______ his notes.
| A．bringing up | B．referring to |
| C．looking for | D．trying on |
Only when your identity has been checked ______.
| A．you are allowed in | B．you will be allowed in |
| C．will you allow in | D．will you be allowed in |