--Who is making much noise? ---It ____ be Timmy. He is sleeping now.
Mo Yan’s books have been sold out in many bookstores _________ his winning of the Noble Prize in Literature.
It makes me very sad whenever I think of my grandma’s______ .
The little girl couldn’t be a student because of her __________.
__________ is really hard __ them to climb such a high mountain.
We must _______ to help the out of trouble.