他心里纳闷儿。
He wonders what is going on.
erhua variant of 纳闷
Every character draws itself, stroke by stroke. Then grab the brush: trace it yourself and hear the word when you finish.
Nice writing!
Chinese words snap together like bricks. Every word below shares a character with this one, so you are already halfway to knowing it.
他心里纳闷儿。
He wonders what is going on.
我纳闷儿他怎么不来。
I wonder why he is not coming.