Watch the stroke order, then trace it yourself.

what to do?; how to handle?
how is it?; how about?
what to say?; how to put it?
what's going on?; what happened?
Why haven't you come yet?
What do you think about this matter? What should we do?
This problem is a bit complicated; I don't know how to explain it clearly right now.
Explore characters by relationship
Characters from the same exam level.
Characters pronounced "za".
Characters with radical "口".