I ofen go to the gym to ___ to keep slim.

A. put out B.help out Cgo out D. work out 该填哪一个啊？

选D。put out熄灭, 用, 发表, 促销生产, 激怒;help out帮助摆脱困境, 帮助完成, 救出;go out
熄灭;work out可以解决, 设计出, 作出, 计算出, 消耗完

D.锻炼的意思

是D、Work out.

全句：I often go to the gym to work out to keep slim.

意思是我经常去健身房保持良好的身材。