英语日常会话问题1.My name is Ann and I am at your service tonight.at

英语日常会话问题
1.My name is Ann and I am at your service tonight.
at 是什么用法,好奇怪的位置
2.What exactly was the problem?
exactly是adv,修饰be动词怎么会放在前面,还是美式口语很随意呢
3.We expect everyone here at Globe Insurance to be hardworking.
here是副词后面又接副词,不会显得重复吗,在语法上有错误吗
4.The accident led to the closure of two lanes.
closure是名词,在这里有语法结构吗,有n+of+n的用法吗
以前不注重语法分析,现在对于句式常有不清楚的地方,