What does this sentence mean?

It's difficult to remember the stroke order of kanji.

He picked up a pen to write down the poem.

It's difficult to understand his mental state.

He is studying about the metamorphosis of insects.

The three states of matter are solid, liquid, and gas.

He is good at reading Chinese text.

Fumiko is my best friend.

He is studying Japanese script.

He wrote a written prayer for the New Year.