13. As a matter of fact, I've been going to the gym for a year now.
事实上，至今为止我到体育馆健身有一年了。
还能这样说：
The truth is that I have been in the gym for a year now.
In fact, I have been working out in this gym for a year now.
应用解析：
fact of life 生活常识;
in point of fact 事实上，实际上;
matter of fact 实际情况，真相;
a fact of life 生活的现实;
the facts speak for themselves 事实本身自明
14. The key to do exercise is to do it regularly.
运动的重点是有规律。
还能这样说：
The most important thing in doing exercises is regularity.
Doing exercises regularly is very important.
应用解析：
keep regular hours 过有规律的生活;
as regular as clockwork 极有规律
15. He goes to the gymnasium every afternoon to sweat off some weight.
他每天下午去健身房以减轻一点体重。
还能这样说：
In order to lose some weight, he goes to the gymnasium every afternoon.
Every afternoon he goes to the gymnasium to work off surplus fat.
应用解析：
sweat blood 拼命工作;
throw sb. into sweat 使某人发汗;
sweat over sth. 辛苦工作;
sweat one's guts out 拼命干
16. How do you feel after you have ridden this stationary bike?
你骑了固定自行车之后感觉如何?
还能这样说：
What is your feeling after having ridden this stationary bike?
Can you express your feeling after you have ridden the stationary bike?
应用解析：
ride high 成功;
take sb. for a ride 欺骗;
ride out 安然度过;
ride up 衣服向上拱，衣服缩上去;
let sth. ride 对某事物不立即采取行动;
ride at anchor 抛锚停泊;
ride for a fall 鲁莽行事
17. What do you think of the facilities here?
你觉得这儿的设备怎么样?
还能这样说：
What is your opinion on the facilities here?
How do you think about the facilities here?
应用解析：
think ahead to sth. 预见，预想;
think back to sth. 想起并重新考虑某事，反思;
think for oneself 独立思考;
think out 仔细考虑某事，想出;
think sth. over 慎重思考某事