“enjoy oneself”可单独使用，表示请自便，玩的开心，相当于have a good.have fun
"enjoy oneself doing sth"表示做某件事情非常的开心，陶醉于做某事，侧重于表现在“做什么”。
知识延展：
双语例句：
This means that you enjoy having a good time.
也就是说，你喜欢玩得快乐。
I hope you'll enjoy yourselves.
希望你们玩得高兴。
Did you enjoy yourself of the party?
你在宴会上愉快吗?
One can't enjoy oneself if he is too tired.
一个人如果太疲倦,就不能尽情享受。
She enjoyed herself making the assistant bring almost everything in the window before finally buying the dress she had first asked for.
"她开心地迫使这位售货员几乎把橱窗内所有的东西都拿出来看看,最后才买下她最初要看的那件衣服。"