I think a little due to the grades that students don't care about learning as much as he should, for example, not to do homework. Do not send this job as a behavior that results in a lower grade.
I think that the grade of the students do not care about learning. As much as they should not attend classes, homework does not work, this is the behavior that resulted in the grades came out less.
I think poor grades because students don't care about learning as much as they should, such as no class, no homework, no send. This is the behavior that resulted in grades came out less.