翻译“如果你上课认真，就没必要在课外去补习”

If you listen to the teacher carefully in class,you don't need to attend a tutorial center.

You won't have need to have remediation if you listen to the teacher carefully

If you are serious in class, there is no need to go to extra-curricular classes

If you attend a lecture carefully, have not certainly needed after school taking lessons after school