interest，n.兴趣;关注;引人关注的性质;吸引力;趣味;业余爱好;利益;利息;好处

例句

By that time I had lost interest in the idea.

那时我已经对此想法失去兴趣了。

fun，n.享乐;乐趣;快乐;享乐的事;嬉戏;逗乐;玩笑;

adj.逗乐的;有趣的;使人快乐的;

例句

I'm all for people having fun.

我完全赞成人们尽情享乐。