. We are short of money, which _____ our difficulties.
| A．adds up | B．adds up to | C．adds to | D．adds |
.
______ his homework, he went on to preview the next lesson.
| A．Doing | B．To do | C．done | D．Having done |
.
In 1989 an international law was passed to stop people _____ waste into the sea.
| A．to put | B．putting | C．not to put | D．not putting |
.
—— John wants to see you today.
—— I would rather he ____ tomorrow instead of today.
| A．come | B．has come | C．should come | D．came |
.
—— Don’t you have a watch?
—— But it has gone wrong. They say it’s not worth ______.
| A．being required | B．to be repaired | C．of repairing | D．repairing |
.
This kind of work ______ great patience, so you should take your time.
| A．calls on | B．calls for | C．calls up | D．calls back |