您贵姓？（nín guì xìng） - A polite way to ask "What's your family name?" 他姓什么？（tā xìng shén me）- What's his family name? 你们叫什么名字？（nǐ men jiào shén me míng zi） - What are your names? (Here name indicates your full name.)

nin guì xìng? what's your last name? I would answer mian gui xing LAST NAME. ta xìng shénme? Her last name is what? nimen jiào shénme mingzi? What are their names? first name usually.

nin guì xìng? 您贵姓？（What's your name?） ta xìng shénme? 他（她）姓什么？（What's his/her surname?） nimen jiào shénme mingzi? 你们叫什么名字？（What are your names? / Can I have (all of) your names?）