Underline the correct form of the verb.

My brother Kevin has always been a fitness fanatic. He believes that if you look after your body, it will look after you. Whenever anyone is ill, he says/will say, "If they had taken care of themselves, they wouldn't get/ wouldn't have got ill. And the same thing happens/will happen to me if I didn't keep fit/ don't keep fit". I would often say to him, "If I were you, Kevin, I would try/ would have tried to slow down a little bit. You will wear yourself out". Last month, however, I went to the doctor's and he told me that I was unfit. He said that If I don't start/ didn't start taking regular exercise, I would be/ would have been in danger of becoming ill. I started going to the gym with Kevin and, after a week, I said to him, "I feel better already. If I know/ had known how good it feels to exercise, I would start/ would have started years ago"!.