I don't think grades are important. Students have different abilities and some of them can't be measured by grades, such as creativity ,abilities to communicate and act.
To start with, I wasn't good at English and seldom got high scores on the exams. But one day, my teacher encouraged me to perform in an English play because of my good pronunciation and lively expressions. To perform well, I studied my lines many times and even dressed up like the character. While we were performing, I could hear my classmates cheering. How excited! Later, my teacher praised me for my wonderful acting and this made me more confident and interested in English.
All in all, grades can be a way to measure students’achievements in schoolwork. However, different interests and abilities can make a student a full man.