1你吃（过饭）了吗？（在吃饭时间前后） 2你去哪（儿）呀？（两个人相遇） 3最近忙什么呢？（有一段时间没联系） 4去吃饭呀？ 去图书馆呀？ 去打篮球呀？ （在大概能猜测出时，也可直接问）

"老外" means "foreign dumbass"... the correct word is "外国人"

现在的中国，人们见面已经很少问：“吃了没？”偶尔也会有，大多数是在饭点前后见到朋友会说。特别是中午饭和晚上饭前后。 你可以用一下方式打招呼： hi，你好。 哇，好久不见，最近怎么样？ hi，你好，怎么样？今天？（这个很口语化）

You can say ''你吃了吗''to your friends，but you cannot say that to someone who dosen't know you。

The above answers are all correct. The reason why some of us ask “ Have you eaten" instead of " how are you" is that " eat" is such an important part of Chinese culture. Guess that's why Chinese dishes are also famous in the world:) x