做及物动词的时候一定要加to
比如：reply to you, reply to work,reply to your letter, reply to my email.
不可以直接说reply to letter/reply email.
作为不及物动词后面什么都不加.
比如：Thank you for your reply.
I am waiting for your reply.(这里的reply是名词）
I am waiting for you to reply.（这里的reply是动词）
希望可以帮到你.