我们也知道，长时间没有变化或缺乏挑战会导致无聊，造成身体和心理上的疲惫。

We also know that a long time without change or challenge can lead to boredom, and physical and mental strain.

youdao

他的身体因疲惫而颤抖，而他的眼中也流露出需要帮助的神情。

His body trembled with exhaustion and his eyes called out for him to be rescued.

youdao

最佳的答案应该是，一天下来，我们的身体已经疲惫了，有必要进行睡眠，以恢复状态。

Probably the best answer is our body is worn out during the day and sleep is necessary to put it back into shape.

youdao

Probably the best answer is our body is worn out during the day and sleep is necessary to put it back into shape.

最佳的答案应该是,一天下来，我们的身体已经疲惫了,有必要进行睡眠，以恢复状态。

耶鲁公开课 - 心理学导论课程节选