Tina has been working so hard at English that she _______the find English exam.
Scientists are convinced _______the positive effect of laughter ______ physical and mental health.
Many of them turned a deaf ear to his advice, ________ they knew it to be valuable.
It is so difficult a question_______ none of the kids could work it out.
Kunming is called“Spring City”, but it _____ snow in winter.
The old black woman sat under the pine tree, her grandsons, ______ around her, ______ to an old story.