--How did she get infected?
--She ________the virus without any protection.
| A．exposed to | B．had been exposed to | C．had exposed to | D．was exposed to |
They__________on the program for almost one week before I joined them, and now we ________on it as no good results have come out so far.
| A．had been working; are still working | B．had worked; were still working |
| C．have been working; have worked | D．have worked; are still working |
He was a bit nervous. He _________his spare breath with a soft sound that was almost heard by the audience.
| A．gave out | B．let out | C．picked out | D．blew out. |
— I failed my driving test again.
— Don't be discouraged. You'll be successful ________.
| A．at times | B．at one time | C．on time | D．in time |
The question was so ________ that there was a ________ expression on the teacher's face.
| A．puzzled; puzzling | B．puzzled; puzzled |
| C．puzzling; puzzled | D．puzzling; puzzling |
We’ve just heard a warning on the radio _______ a typhoon may be on its way．
| A．what | B．when | C．which | D．that |