John _____ knowledge of radio just by staying around the radio station.
| A．caught on | B．worked up | C．took up | D．picked up |
My parents were not happy as they don't approve ____ out at night．
| A．of Mary and me staying | B．of me and Mary staying |
| C．to Mary's and my staying | D．when Mary and me stay |
We haven't seen each other for 20 years, but I recognized him _____ I saw him．
Which of the following is wrong ?
| A．immediately | B．the moment |
| C．as soon as | D．while |
Life is the most important in the world so we should never compromise _____ safety standards．
| A．with | B．between | C．on | D．in |
Generally speaking, when _____ according to the directions, the medicine had no side effect．
| A．take | B．taken | C．to take | D．to be taken |
________ it is expected that students come to college with the ability to solve most problems in their study by themselves , this is not always the case.
| A．When | B．While | C．For | D．As |