1 Have a crush on someone
迷恋，爱慕当我们说Have a crush on someone的时候，意思是喜欢上某个人，这通常是指短时间内的迷恋或爱慕。I had acrush on you in junior high school.上初中那会儿我有段时间特别喜欢你。
2 Be smitten with
突然爱上
单词smitten是“smite深深的影响”的过去分词，在这里意思是是“突然深深的迷住了。“Look at those lovebirds！They are toally smitten with each other. 瞧那对情侣！他们看起来是多么深爱对方啊。3 Head over heels in love
坠入爱河这个表达的意思是“爱得神魂颠倒”，用来形容人完全坠入爱河的状态。Sammy is so head over with Emily,he mentions her every five minutes.萨米被爱米莉迷的神魂颠倒，他每五分钟就看她一次。4 Be swept off someone's feet
彻底的爱上这个表达的含义是对某人完全倾心，爱的神魂颠倒。I am completely swept off feet by his glamour.我已经完全被他的魅力折服了。5 Fall for
爱上“爱上某个人”最常见的说法除了fall in love with someone以外还可以说fall for someone,同样可以表示迷恋上某个人。She fall for her best friend.她爱上了她最好的朋友。