首先区分一下他们的词性.
relax是动词,意思是 使.放松,例句：I always go swimming to relax myself on weekends.
翻译：周末我总是通过游泳来放松自己.
relaxed是形容词,意思是感觉放松、轻松的.例句:I feel rather relaxed after crying.
翻译：哭过之后,我感觉相当轻松.
relaxing也是形容词,意思是 .令人放松的.例句：This school trip is very relaxing.
翻译：这次学校旅行令人很放松.
祝你学有所成.