单选题 I__on a sofa because my grandparents have been here to spend the weekend.

单选题 If we keep wasting so much energy.__are that our oil wells will dry up and the environment will be destroyed.

单选题 ---I will have to think about it again.
--If you_ you may lose the opportunity to compete altogether.

单选题 The Voice of China has set up a stage__ some people can achieve their dreams.

单选题 The further falling of the stock market as reported today has__ a fresh wave of selling.

单选题 You should study the details of the policy__ before you sign it.

单选题 Exploring__ space is exciting, yet dangerous. There is__need for both robots and humans
For space exploration.

单选题 You may imagine what great difficulty I had__complicated ideas in simple English.