The Nile River ____ flood large areas but now the water ____ produce electricity. [ ]

29．—- I wonder how much you charge for your services.—- The first two are free ____ the third costs $30

— I have come to say good-by.— What time_____?[ ]

I think Tom,_____ you,is to blame for the broken window[ ]

When Mr Fang smelt the food, he stopped ___________.