Only when___________ according to the directions can the medicine be quite effective.
| A．taking | B．taken |
| C．being taken | D．having been taken |
Europe has achieved more in controlling the AIDS virus than Asia in the past ten years, _________ the number of people infected with the virus is going up sharply.
| A．when | B．that | C．so that | D．where |
Hardly ___________the door when he rushed into the office out of breath.
| A．I opened | B．did I open | C．I had opened | D．had I opened |
The driver was at ___ loss when ____ word came that he was forbidden to drive for speeding.
| A．a; / | B．a; the | C．the; the | D．/; / |
We want such materials ________ can bear high temperature and pressure.
| A．that | B．as | C．what | D．which |
Her sister has become a lawyer, _____she wanted to be.
| A．who | B．that | C．what | D．which |