in English：it means anything that requires minimal brain activity to accomplish. Usually said about decisions that are made, implying the decision was easily reached.在英文里，no brainer指的是无需废脑筋的事情。一般指的是做出了一个决定，而这个决定很简单就可以做到；
The decisions we make and the activities we do throughout the day require a brain. 我们所做的决定和行为都需经过大脑的思考。That's right! Even the simplest of tasks require some bit of brain activity to perform. 即使是最简单的任务都需要一点点大脑的协助.Without a brain, well, we'd be dead and unable to do anything!没有大脑，生命就会不再，我们也不能做任何事情；
Still, despite this, there are menial tasks or easy decisions that are sometimes considered to be 'no-brainers,' 即使如此，依然有没有意义的工作和简单的决定存在，而这些被认为是no brainer; meaning a person shouldn't even have to use their brain to think when performing said tasks or making said decisions. 意思就是说人们在做这些事情和决定的时候根本无需用大脑去思考就可以；For example, if someone is feeling generous and offered you a million dollars for absolutely nothing in return, many would consider the acceptance of that offer to be a 'no-brainer.' 例如： 如果有人很慷慨地免费给你一百万美元，很多人都会接受，因为这件事就是no brainer;
that was a really easy decision, could be called no brainer. Of course I would go out with her.
For US firms, the decision to manufacture overseas has long seemed a no-brainer.