It’s ten years since the scientist ____ on his life’s work of discovering the valuable chemical.
| A．made for | B．set out | C．blocked out | D．turned up |
The question occurred to me ______ we were to get the machine needed．
| A．that | B．what | C．why | D．where |
_______ 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 |