PartⅢ Passage
Metro Signs
There are variety of signs used in a metro or for a metro.
In China，different cities use different metro signs，which can be also called as logos.These signs not only are metro identification，but also can represent cities and metro companies.They are used at outside of the metro stations.
Inside of a station，there are more signs.Some signs are in letters，some of them are in symbols，but most of them are in both letters and symbols.Among these signs，the most we can see are the“EXIT”signs in green，which can tell us the ways to get out of the station.The bathroom signs are not in letters，usually in symbols of a man and a lady together to point out where the WC is.
Some signs are in red color.As we all know in transportation，red means stop or prohibition.So the signs with red color strongly advise that some human behaviors are not allowed in the designated area，like“No Smoking”，“No Drinks”and“No Pets”.If people don't obey the signs in the designated area，they will get themselves in trouble.
Also，there are some signs for instructions，like“Handbrake bottom only used when fire alarm on”.
The development of the metro in the globe are not the same.The requirements and standards of metro signs are also different.
New Words and Expressions
地铁标识
地铁站内和站外有各种标识。
在中国，不同的城市使用不同的地铁标识，也可以称为标志。这些标志不仅是地铁的标识，也可以用来代表城市和地铁公司。它们使用在地铁站外。
在地铁车站内有更多的标识。一些标识使用字母，一些使用符号，而大多数标识是同时使用字母和符号。在这些标识中，大部分我们可以看到的是绿色的“安全出口”标识，告诉乘客如何走出车站。洗手间的标识不是字母，通常是一个男人和女人的形象一起指向洗手间的位置。
一些标识的颜色是红色的。我们都知道，在公共交通中，红色意味着停止、禁止。所以红色的标识强烈建议一些人的行为在指定区域内是不允许，像“禁止吸烟”“禁止喝饮料”和“禁止携带宠物”。如果人们不遵守指定区域内的标识，他们会让自己惹上麻烦。
同时也有一些标识是指示性的，如“手动刹车按钮仅在火灾报警时可按下”。地铁在全球的发展并不同步，所以地铁标识的要求和标准也不同。