look sb in the eye中eye为什么不加s

look sb in the eye中eye为什么不加s 为什么是look sb in the eye而不是eyes?是不是很多类似词组都是单数? look sb.in the 英语：look sb in the eye 与 look sb in one's eye 区别空气是几种单质和几种化合物的混合物 这句话对吗?那 空气成分固定不变的 He smiled at the loving look in my eye why don't you look me in the eye? 请问look sb.in the face look me in the She look me in the eye and told me the whole story.look me in the eye是固定短语么? i saw the look in your eye 这里的look怎么翻译比较好? look at my eyes 和 look me in the eye啥区别 击中某人的眼睛 英文翻译hit sb. in the eye 为什么要用in? sb look nice in look nice in sb. look at sb in th mirror,in the local mine one in the eye in the eye hit与介词搭配用法为什么是hit sb on the headhit sb in the eye?如何区分 look yourself in the eye什么意思when this is achieved, you can look yourself in the eye and say that your enterprise is fully energised