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。