You should contribute to group work.
Fernando is very tired and is assigned a strenuous group assignment during history class.
Fernando wants to go home.
Fernando works hard with his group to quickly knock out the assignment so that he can go home and rest.
Fernando wishes his group mates good luck and goes home without helping.
Fernando and his group are given an A on the assignment and are given a voucher to skip one day of class for free.
Fernando's group mates turn in the assignment but tell the teacher he didn't participate causing him to fail the assignment.