She didn't know that the company could afford to advertise such low prices because these were just "to get customers in the door." Indeed, there is hardly enough money there to pay the trainers, who are really working hard. The trainers exhaust themselves, and end up with pulled muscles, tendonitis, and other occupational injuries.
她也不知道，廣告上強力促銷的瘦身價碼只是「入門價」，當然不算貴；而且正像業者形容的，瘦身課程是「辛苦錢」，是美容師使出全身力氣，外加肌肉拉傷、韌帶發炎等職業病換來的。