John said he had been working in the office for an hour, _______ was true.
| A．he | B．this |
| C．which | D．who |
We cannot be about our work．Any small mistake may lead to a serious accident．
| A．very Particular | B．too cautious |
| C．extremely considerate | D．quite serious |
It was_________ back home after the experiment.
| A．not until midnight did he go | B．until midnight that he didn’t go |
| C．not until midnight that he went | D．until midnight when he didn’t go |
Using _____ illegal drugs can lead to health problems, and it can be _____ stain on one’s life.
| A．不填；the | B．the; the | C．the; a | D．不填； a |
_____ Chinese basketball player Yao Ming will probably return to the NBA if he can recover from _____ earlier injury.
| A．不填; an | B．The; 不填 | C．A; an | D．The; the |
Later，I realized that I didn’t know his name or the least bit about him，________intend to ask．
| A．nor did I | B．I did not | C．nor I did | D．either did I |