Some students think a difficult exam just like a challenge and the more difficult it is,the more (把more拿掉）better it will be.They say a difficult exam can helps（把helps改成help) students to(删掉to) find out where they are weak in their studies and improve their learning methods.
Others,however,are against a difficult exam,in their opinion,if it is very difficult,they may become discourage（加d)and feel terribly （改成terrible)about their studies.
I prefer an exam neither too difficult nor too easy,a very easy exam in（改成is) not good for teachers to learn how we are getting with our studies,but too difficult exam will make us lose our heart.