reply,answer,respond的区别

answer 作“回答”讲时，是一方提出问题另一方回答常用词，较常用，我们既可以说 answer a question,回答问题，也可以说 answer the doorbell,听见门铃响去开门，还可以说 answer the telephone,接电话。Excuse me, can you give me an answer of this question?

reply较正式，除了后面跟直接引语或以that开始的句子外，一般只用作不及物动词，后面连用to,表示回答别人的问题（话语、信件、祝贺、攻击等）特别是在写信中常用此句开头：Thank you for your reply. Do you have any suggestions as to how we should reply to his questions?关于如何回答他的问题，你有没有什么建议？

respond 作“答”、“回答”讲，为正式用语，常与介词to连用。通常只对号召、职责、请求、紧急情况等做出反应或回应。She never responded to his opinion.她从未对他的意见作出过反应。/I greeted him, but he didn't respond. 我跟他打招呼，但他没理我.