Before traveling in space you must know what it might feel likein an imaginary environmen

问题补充：

Before traveling in space, you must know what it might feel likein an imaginary environment.

A. to travel

B. traveling

C. to be traveling

D. travel

答案：

(答案→)A. to travel

B. traveling

C. to be traveling

D. travel

解析：本题易受到feel like doing sth的影响而误选B, 此处feel like的意思为 “感觉象什么”, it 为形式主语,真正的主语为不定式短语。句意：太空旅行前，你必须知道在模拟环境下行走时的感觉。