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　     Soon computers and other machines will be able to remember you by looking at your eyes! The programme works because everyone's eyes are different. So in the future you won't have to remember a number when you want to use a machine or take money out of a bank. You'll just have to look at the machine and it will be able to tell who you are. The eye-recognition(眼睛识别) programme is tested in shops and banks in the USA, Britain and Italy.

       Scientists are working on other systems, such as knowing you from the shape of your face or hands or even your smell! And machines can already tell who you are from your voice or your fingerprints(指纹). But eye-recognition will replace other ways of finding out who you are. It is better, because your eyes don't change as you get older, or get dirty like hands or fingers. And even twins have different eyes, so the programme can be up to 94% correct, depending on how good the technology is. In Britain, it was found that 91% of the people said that they liked the idea of eye-recognition.

下面左图示意某地区某时刻的气压形势分布图，右图是左图中40°纬线穿越的河流的剖面图。左图中⑤地与②地相比（    ）

给出四个命题：①函数是其定义域到值域的映射；②$f\left(x\right)=\sqrt{x-2}+\sqrt{2-x}$是函数；③函数$y=2x\left(x\in N\right)$的图象是一条直线；

④$f\left(x\right)=\frac{x^2}{x}$与$g\left(x\right)=x$是同一个函数．其中正确的有 (　　)