Write, what do you think about vegetarianism.

Или есть другие варианты?

Wtite down about your attitude toward vegetarianism. (?)

How do you concern to vegetarianism. (?)

What's your opinion towards vegetarianism?

It's cool, really!)) I'm on the right track. I have had option "how you feel about vegetarianism".))

Very good!

Другие варианты, что я написала, неестественные?

This one works: Write DOWN what you think about vegetarianism.

Do не нужно?

Я, наверное, не так изучила тему: я бы написала
Write down what do you think about vegetarianism :)

WHAT DO YOU THINK, это вопрос сам по себе. Но тут, напиши что? WHAT YOU THINK.

Thanks!