— There'ssomeone knocking on the door. Who _____it be?— It must be Mary. She promised to be here at 8:00.
—We need to buy some summer clothes, John. —Oh, I never know ________when I'm in the store.
—Isn't Miss Brown here yet? —No.________, she's not here yet.
The temperature is high enough ________water into vapor(蒸汽).
There is no good for the parents to provide everything________their children.
Wait until you are________in.