My study of biology has ___ much of my spare time, ____ it has given me a great deal o enjoyment.
Please write me ____ you arrive in New York.
—Would you like to come to dinner tonight? —I’d like to, ___ I’m too busy.
___ I know he will stay here for half a year.
—I don’t like chicken _______ fish. —I don’t like chicken, _______ I like fish very much.
We can surely overcome these difficulties _,___ we are closely united.