—Listen! Someone is singing in the next room. Who ____ it be? Is it Li Wei?—No, it ______ be her. She is at school now.
We really don’t know _________ with our problems in learning English.
They were walking ________ a forest after they swam _______ the river .
_______should not be allowed to get ears pierced.
What would you do if you had _________ dollars ?
Jimmy is _________one-year-old boy and he has_________8-year-old sister.