在英语中，"玩得快活"可以用以下几种表达方式来表示：

Have fun: "快乐"或"玩得开心"。例如：
"We had a great time at the amusement park. We really had fun." (我们在游乐场度过了美好的时光。我们真的玩得很开心。)
"Make sure to have fun at the party tonight." (今晚记得在聚会上玩得开心。)
Enjoy oneself: "享受"或"玩得愉快"。例如：
"We went to the beach and really enjoyed ourselves." (我们去了海滩，真的玩得很愉快。)
"I hope you're enjoying yourself at the concert." (希望你在音乐会上玩得愉快。)
Have a good time: "玩得开心"或"过得愉快"。例如：
"I'm glad you had a good time at the movie." (我很高兴你在电影院玩得开心。)
"We're having a good time at the beach." (我们在海滩过得愉快。)

这些表达方式都是英语中常用的表达玩得快活的方式，它们都来自英语中对于快乐和愉快的描述。