第3个回答 2005-11-13
'liufuduo'的回答 is fairly right, but the answer is still not complete.
"fall in love" means fall for someone, in this sense "be in love (with)" could be the same. It could be love from just one side and another person may still not know(e.g. "I'm so in love with her but she doesn't even know" or "She fall in love with him at first sight" or "Andy is in love"). In a word, the "love" here 可以是单相思或柏拉图式的精神恋爱。
If emphasize the word "谈" in "谈恋爱"(一定要有两个人做主语,e.g.relationship), the translation should be "we/you/they"+"are in love"/"are in love with each other",表明彼此相爱着的一种维系着的状态。
相对地, "they fall in love with each other" should have a more precise translation "他们一同坠入了爱河",仍侧重最初“坠入”时的情境。
谢谢!