— Hello, may I have an appointment with the doctor?
— ___.
| A．Sorry, he is busy at the moment. |
| B．Why didn’t you call earlier? |
| C．Certainly. May I know your name? |
| D．Sorry，he doesn’t want to see you. |
To be honest, I would rathermy dog out, which made so many troubles.
| A．not had let | B．I had not le | C．not let | D．not have let |
Jack is late again. It isof him to keep others waiting.
| A．typical | B．common | C．ordinary | D．normal |
Jack, who pretended, heard, however, every word that was said.
| A．not listening | B．not to be listened | C．not to be listening | D．not having listened |
The old man __________ in Tibet for two years as a volunteer teacher；it is an experience he often mentions.
| A．served | B．serves | C．is serving | D．has served |
Qian Xuesen tried many times _________ he found the solution to the puzzle about space technology.
| A．after | B．before | C．since | D．when |