. ___ to nuclear radiation, even for a short time may produce variants(变异体)of genes in human bodies.
Although the number of competitors ___ limited, a number of our classmates ___ eager to take part in it.
We don’t need to do ___ extra work this evening. The day’s work was almost at ____ end now.
He talks about Rome as if he _________there before.
I was on the highway when this car went past followed by a police car. They ______ at least 150 kilometers an hour.
All the teachers discussed the plan that they would like to see __________ in the next school year.