Some students

I have two to three students who I think have given up. They do a good job of looking busy but don't seem to achieve much. I have tried to encourage them. Two of the students have Fs and that doesn't seem to matter. Any suggestions? I have one young man that this class is a real struggle for him but he stills asks questions or ask the girl beside his for help. His ability is far below the ability of the two who are not working. I have had this problem before and try different things with the students but I think I am getting old and can not think of anything to try. Please help the old lady in need.