—How far can you run without stopping?
—________. I've never tried.
| A．Don't mention it | B．That's all right |
| C．I have no idea | D．Go ahead |
_______ with care, one tin will last for six weeks.
| A．Use | B．Using | C．Used | D．To use |
When deeply absorbed in work, ______ he often was，he would forget all about eating or sleeping.
| A．that | B．which | C．where | D．when |
George said that he would come to school to see me the next day, but he ______.
| A．wouldn’t | B．didn’t | C．hasn’t | D．hadn’t |
Jerry did not regret giving the comment but felt ______ he could have expressed it differently.
| A．why | B．how | C．that | D．whether |
One learns a language by making mistakes and ______ them.
| A．corrects | B．correct | C．to correct | D．correcting |