Could you check my writing and correct mistakes thanks in advance only about 10 sentences

How your children are doing at school. Do they get good grades in their lessons? 
What subject are usually taught in USA? 
Here in Russia older students have lots of subjects. It is very difficult to study perfectly with excellent grades as demands are very high and a lot of homework is given every day.
For example, English level is equal to C1, and in order to pass you must do an exam which is similar in structure to FCE.
Children must work hard and lots of teachers think that their subject is the most important.
Teachers are very strict in Russian schools.
I think Russian school education should be reformed and after grade nine students should have an opportunity to choose subjects which are prerequisites for their future career.

From Francesca - please let me know if you would be interested in having lessons!