at first 与 first of all 有什么区别?

at first
首先,最初
1.We didn't trust him at first,but his charming manner completely disarmed us.
我们开始时并不信任他,但他令人愉快的举止完全消除了我们的疑虑.
dict.cn
2.At first he refused to accept any responsibility but he ended up apologizing.
最初他拒不承认有任何责任,到头来还是道了歉.
3.At first we used hand tools.
首先我们使用手工工具.
first of all
首先
1.Marriage is,first of all,a contract which must be governed by justice.
婚姻首先是一种契约,它必须以公正为制约.
2.First of all,we are today as Senator Kennedy has admitted,the strongest nation in the world militarily.
首先,正如肯尼迪参*所承认的那样,我们是世界头号大国
3.First of all,let me tell you the news.
首先,让我告诉你这个消息.