Please explain the use of 位 in this interrogative sentence.
(This is from a Textbook that I am using.) 服务员说：二位要吃一点儿什么？。 I understand that 位 means seat in Mandarin. The translation in the textbook says, "What would you two like?" Is 二位 replacing 你们？Are there other examples of this type of pronoun modification?

Question

Please explain the use of 位 in this interrogative sentence. 
(This is from a Textbook that I am using.) 服务员说：二位要吃一点儿什么？。 I understand that 位 means seat in Mandarin. The translation in the textbook says, "What would you two like?" Is 二位 replacing 你们？Are there other examples of this type of pronoun modification?

Answer

二位 = two people.

位 = polite counter for persons! That is why it is used in this setting.

Answer

The sentence "服务员说：二位要吃一点儿什么？" means "what would you two like to eat ?“二位”is the same meaning of " 你们”But use the "二位" is show respect .Usually use "二位" in restaurant ,hotel and so on ..For example ,when u go to the restaurant ,the waiter will say "先生几位 ？"means "How many people would in this dinner ,sir ?" The " 几位" is the same meaning of "多少人" , means "how many people ?"

Answer

“位”like the words "a man", and this word "位" can't use at the vais allons.
“位”这个字可以解释为“个+人”，这个词不能用在第一人称。
ex. 服务员说：“请问您几位？”

Answer

I think Eliot's explanations are most correct.  （两）位 just is a polite and commendatory term which is equal to "one" or is used for replacing two people.  For example, 这位 means this(这） one（位）.  两位同志 two comrades, in this expression, 位 is a quantifier.  It is like the use of piece when using a piece of paper in English.

Answer

位是数量词，例如：一个人，两个人，三个人，二匹马，三头牛，其中“人、匹、头”都是数量词。
二位=tow people,这里是较礼貌的用法。