You received an email from your english friend, harry. He asked for your advice on how to keep fit. Read part of his email below. Hi, i enjoy my job, but i often sit at a computer all day. I don't get much exercise, so i often feel tired. I consider going to the gym to improve my health, but i often work very late. Could you recommend something else i should do to keep fit? do i really need a personal trainer or can i do it by myself? also, do i need to buy any equipment to do exercise? does it cost much to buy them? i look forward to your reply. Write an email responding to harry. You should write at least 120 words. Do not include your name or addresses.