After Yang Liwei succeeded in circling the earth our astronauts desire to do is walk in

问题补充：

After Yang Liwei succeeded in circling the earth, our astronauts desire to do is walk in space.

A. where

B. what

C. that

D. how

答案：

A. where

(答案→)B. what

C. that

D. how

解析：在题干中，谓语desire to do 之后又出现了谓语动词is,说明is 之前是主语从句。能够引导主语从句并在其中充当主语的只有what。