1. use your loaf —— 动动脑子

　　你跟别人说这个习语，就是说用有点生气的口吻让别人做事多动动脑子。

　　e.g. I Going to be a useful boy, so long as you use your loaf .

　　只要运用你的头脑，就会成为有用的年轻人。

　　e.g. You haven’t even switched the thing on. Come on, Jamie, use your loaf!

　　你连开关都没看。天哪，杰米，长点脑子吧!

　　2.The lights are on but nobody’s home .

　　light意指灯，on意指亮着的，开着的，nobody意指没有人，home意指在家;the lights are on but nobody’s home系指家里灯亮着但没有在家，喻指心不在焉，身在曹营心在汉。

　　e.g. She really has no clue- the lights are on but nobody’s home!

　　她完全抓不着头绪——脑子笨的像头猪。

　　e.g. Because the lights are on but nobody’s home, she cannot understand what the teacher is saying.

　　因为她心不在焉，所以根本不懂老师在说什么。

　　3. all thumbs 笨手笨脚

　　Thumbs: 大拇指。如果一个人十根手指都是大拇指，那连握东西都握不住怎么干活。

　　e.g. Dick isn't very good using tools around the house. He's all thumbs: when he hammers a nail he's likely to end up hitting his finger instead. And you'd be shocked to hear the bad language he uses when that happens!

　　Dick在家里用工具干活是不太行的。他总是笨手笨脚，当他要敲一个钉子的时候，他往往会敲到他自己的手指上。把自己敲痛了，他就破口大骂，你听了真会吓一跳。

　　e.g. He’s all thumbs when it comes to his girlfriend. He just can’t do anything right!

　　他一遇到他女朋友，就笨手笨脚的，什么事都做不好。

　　4. not the brightest bulb in the box / on the tree / in the chandelier. 他/她可算不上最聪明的

　　字面意思就是：并不是盒子里/圣诞树上/吊灯里最亮的灯泡。其实内在意思是很婉转地在说你笨。

　　e.g. He's not the brightest bulb, is he?

　　他还真不怎么聪明，是吧?

　　5.bean brain 没脑筋

　　脑子小得像颗豆那样，到底能用不能用?答案：没什么用。

　　e.g. I can't imagine Bill is such a bean brain. He brought the camera and forgot the film.

　　无法想象比尔这么没脑筋。他带了相机，却忘了带底片。

　　e.g. I have never seen a bigger bean brain like you.

　　我从没见过比你更蠢的蠢才。