All over the world many kinds of student are here.They want very hard work all part of book bt many teacher are not take care this student.It's cause many student are not understand to learn.That's cause many student are not grow up.it is very danger to a student life.I say this teacher please take care all student to his learn.If any student don't understand please u learn this student very slowly.That's a student learn easily it's very good effect to his life.