5.A:You look a little worried,Betty.(76)What's the matter/What's wrong with you?
B:Mum,it seems that I'm getting heavier these days.
A:That's a problem.Can I offer you some advice?
B:Sure.(77)What should I do/What's it?
A:First of all,stop eating too much.Secondly,(78)take more exercise/do some sports.
B:But I'm afraid I am too busy to exercise.
A:Then why not join a club on weekends?
B:(79)What kind of club should I join/What club?
A:You can join the swimming club.You want to learn to swim,don't you?
B:(80)That's a good idea/Yes.Thank you,mum.
A:You're welcome.I hope it will help.