When he was alive, the old scientist used to say that knowledge ＿＿＿＿from practice and he gained his experience by doing a lot of practical work.
| A．was coming | B．had come | C．comes | D．would come |
_______ information cost him many chances of finding jobs．
| A．Lack of | B．Short of | C．Lack | D．Lacking of |
How many more decades will have to pass ____ scientists succeed in providing a cure for cancer?
| A．when | B．since | C．before | D．until |
--- Where will you start your work after graduation?
--- Mmm, it’s not been decided yet．I _______ continue my study for a higher degree．
| A．can | B．must | C．would | D．might |
Many clothing manufacturers now substitute artificial silk _____ natural silk to cut down costs of production．
| A．with | B．by | C．for | D．of |
--- Where are you, Nancy?
--- Here in the sitting room, _______ to Professor Smith．
| A．is writing | B．write | C．to write | D．writing |