. ___ to nuclear radiation, even for a short time may produce variants(变异体)of genes in human bodies.
To our ______, the result of the experiment is much better than we expected.
— Remember the first time we met, Jim?— Of course I do. You _______ in the library.
We hadn’t been out for long _________ she felt sick.
________ a little money, Jane was able to buy her mother a lovely new watch.
The weather turned out to be fine yesterday. I ________the trouble to carry my umbrella with me.