at the beginning ,in the beginning 什么区别 那个加OF? first first o

at the beginning ,in the beginning 什么区别 那个加OF? first first of all firstly 区别是什么啊

1.in the beginning是单独使用作时间状语的.
e.g.In the beginning,I couldn't understand what you said.
at the beginning of +名词,表示在什么事情的刚开始的时候.
e.g.At the beginning of my speech,I'd like to share with you a picture.
2.当first和firstly作副词用的时侯,如果“用于分开并依次列举所述各点”时,是没有什么区别的,可以替换.
e.g.First(ly),I'll mention the advantages,then I'll mention the disadvantages.
但当用于修饰行为动词时,则只能用first.
e.g.I must ask my parents first
When did you first go to the country?
另外有一点小区别如下：
first 更常用于做某事的步骤;
at first 常用于讲述事情的起初;
first of all 常用于提出观点的开头语.