乐此不疲

滑雪真的太上瘾啦,从早滑到晚,乐此不疲

Skiing is really addictive, skiing from morning till night, never getting tired

每天老婆做饭,虽然辛苦,但他乐此不疲,毫无怨言

Every day his wife cooks, although it's hard work, he enjoys it tirelessly and never complains

为什么有人觉得坚持锻炼很难,而有人却乐此不疲

Why do some people find it hard to persist in exercising, while others enjoy it tirelessly?