Hit a/the wall:
To reach a point where you feel unable to continue doing something because it is very difficult.
“Hit a wall” 或 “hit the wall” 直译过来是 “撞墙”，它实际上用来表示 “体力上太疲倦或者精神上太累，以至于无法继续手上的事情”。这个短语尤其常用在谈论跑步、锻炼等话题中。
例句
The marathon was going well until the halfway point. I hit a wall and had to give up.
那场马拉松一开始非常顺利，但跑到一半时我体能达到极限，不得不放弃比赛。
I’ve hit the wall with my exam revision – I’ll stop for dinner and will hopefully feel more motivated afterwards.
考试复习让我累极了，我要歇一会儿，吃个晚饭，希望吃饱喝足后有动力接着复习。
After just half an hour at the gym, I hit a wall. I don’t think I’ll push myself so hard next time!
我健身才半个小时就达到了极限。我想我下次不会再把自己逼得那么厉害了
