To keep healthy, Professor Johnson ______ cycling as a regular form of exercise after he retired.
A. carried out B. caught on C. took up D. made for
One way to understand thousands of new words is to gain _____ good knowledge of basic word information.
A. 不填 B. a C. the D. one
It was announced that only when the fire was under control ____ to return to their homes.
A. the residents would be permitted
B. had the residents been permitted
C. the residents had been permitted
D. would the residents be permitted
The driver _____ for the accident had not been driving carefully.
A. blamed B. being blamed
C. to be blamed D. blaming
You should read the _________ in the car repair manual (手册) carefully before you start to work on it.
A. instructions B. descriptions
C. introductions D. explanations
_____ to nuclear radiation, even for a short time, may produce variants (变异体) of genes in human bodies.
A. Exposed B. Being exposed
C. Having exposed D. After being exposed
