_____to nuclear radiation, even for a short time , may produce variants(变异体) of genes in human bodies.
I work in a business ___ almost everyone is waiting for a great chance.
Last moth, part of Southeast Asia was struck by floods, from ___ effects the people are still suffering.
If you go by ____ train, you can have quite a comfortable journey, but make sure you get ___ fast one.
If you grow up in ___ large family, you are more likely to develop ____ ability to get on well with ____ others.
--It is often said that ______teachers have _______very easy life.