All in your head
都是你想象出来的
I can assure you that it's all in your head.
我可以保证你想多了。

Don't put all your eggs in one basket.
不要把鸡蛋放进一个篮子里。

All in a days work
小事一桩
A：Hey thanks for helping me a lot.
谢谢你帮我这么多。
B：Hey don't mention, it was all in a days work.
不客气，小事一桩儿。

Hey all eyes on the blackboard.
嘿，眼睛都看黑板。

Thanos arrived and then all hell broke loose.
灭霸来了，灾难也就降临了。