Sometimes it's easier actually not touch it to the metal, -- I should have- TA: It's hard to see if it's moving or not.

有时候它更容易不接触金属，我本应该-,助教：很难看到它是否移动了。

麻省理工公开课 - 化学原理课程节选

It's not that hard to stay in touch.

保持联系不算难。

一起长大的朋友 - SpeakingMax英语口语达人

For me, it's hard to relate sort of that touch with the time.

我很难把那种内心的感觉,和时间联系起来。

麻省理工公开课 - 电影哲学课程节选