You shouldn't lie to your family.
May is struggling in school and her parents ask how her grades are.
May wants to hide the truth about her grades.
May finds a way to change the subject, so she doesn't have to lie.
May tells her parents that she is doing well in school currently.
May's parents assume she's doing fine and don't ask again for awhile.
May's parents find out from the school that she did not tell the truth and ground her.