Why with 为什么

Structure (Subject) + 为什么 + Verb？

为什么 (wèishénme) asks "why?". Like other question words, it stays in place (it isn’t fronted when the subject comes first): 你为什么不来？ The answer usually starts with 因为 (because). It doesn’t combine with 吗.

Examples

你nǐ为wèi什shén么me不bù来lái？
Why aren’t you coming?
他tā为wèi什shén么me迟chí到dào？
Why is he late?
为wèi什shén么me这zhè么me贵guì？
Why is it so expensive?

Levels are indicative: they follow the standard Chinese Grammar Wiki (AllSet Learning) progression, not an official HSK 3.0 mapping. We never assign levels by eye.

This point and the other 370, with audio on every example, inside Wanyu.