asking questions

use 吗 to ask “yes or no” questions
这书是你的吗?
Is this your book?

use 什么 to ask “what” questions
这是什么?
What is it?

use 谁 to ask whom / who
他是谁?
Whom is he?

use 多少 to ask how many/how much
那里有多少人?
How many people are there?
这条裙子多少钱?
How much is the skirt?

use 怎样/怎么 to ask how
这道数学题该怎么做?
How to solve this mathematics question?

use 哪个 to ask which
哪个比较适合我?
Which one is right for me?