keen  
 adjective uk/kiːn/ us/kiːn/
  (EAGER)      
 B1 热衷的;热心的;渴望的
very interested, eager, or wanting (to do) something very much
  They were very keen to start work as soon as possible. 他们渴望尽早开始工作。 
 Joan wanted to go to a movie but I wasn't keen (= I didn't want to go). 琼想去看电影,可我不想去。 
 She's a keen tennis player. 她热衷于打网球。 
 She's keen on (playing) tennis. 她很喜欢打网球。 
UK My son's mad keen on cycling. 我儿子对骑自行车很着迷。 
 He's rather keen on a girl in his school (= he is very attracted to her). 他迷上了学校里的一个女孩子。 
 - More examples
 - Prince Charles is a keen polo player.
 - They've been keen walkers ever since they read about the benefits of exercise.
 - Doctors are short of time to listen and are therefore keen to dish out drugs whenever they can.
 - "What did he think of your suggestion?" "I don't think he was too keen."
 - With an election approaching, the prime minister is keen to maintain his popularity.
 
  (STRONG)         
  强烈的,激烈的
extreme or very strong
  Many people are taking a keen interest (= a very great interest) in the result of the vote. 许多人对投票结果表现出浓厚的兴趣。 
 C1 敏锐的;敏捷的
very good or well developed
  a keen sense of smell 灵敏的嗅觉 
   (SHARP)      
 literary尖利的;寒风刺骨的 
very sharp
  a keen north wind 寒冷刺骨的北风 
 Idiom  
(as) keen as mustardidiom UK old-fashioned 极为热切;极感兴趣
very eager and interested in everything
 keen         
verb [ I ]  literary uk/kiːn/ us/kiːn/
 (尤指因某人死去而)恸哭
to make a loud, long, sad sound, especially because someone has died
 keenness
noun [ U ] uk/ˈkiːn.nəs/ us/ˈkiːn.nəs/
 热衷;渴望
the quality of being keen