eg. He's keen on music.
他很喜欢音乐。

Molly is very keen on the music master.
莫莉很喜欢那位音乐老师。

be keen on doing sth 喜欢做某事

She's keen on growing roses.
她喜欢种玫瑰花。

2.would rather not 宁可不

eg. Well, I would rather not eat now. I do not feel well.
嗯，我现在不太想吃东西。我不太舒服。

eg. I do not know about you but I would rather not buy toxic anything.
我不了解你的情况，但我是不愿购买任何有毒的东西。