The retired professor, _____ in his new book in the past three years, hasn’t realized the decline in his health．
| A．involved | B．being involved |
| C．having involved | D．to be involved |
All the scientific evidence ______ that increasing use of carbon dioxide ______ the rise of the earth’s temperature.
| A．show; result in | B．shows; result from |
| C．shows; results in | D．shows; results from |
Without the ‘ greenhouse effect’, the earth ____ be about thirty-three degrees Celsius cooler than it is.
| A．should | B．would | C．will | D．must |
During the Middle Ages, a conventional artist was not interested in showing nature and people _____they really were.
A. who B what C. like D. as
________volcanoes now for many years, I am still as enthusiastic about my job as the first day I first______.
| A．Studied, started | B．Have studied, started |
| C．Having studied, started | D．Having studied, starting |
Film has a much shorter history, especially when ______ such art form as music and painting.
| A．having compared to | B．comparing to | C．compare to | D．compared to |