▲at the top of 的用法

(1)在…的上部(顶部)

In a few minutes he was at the top of the tree. 没几分钟，他就爬到了树梢。

At the top of the stairs, she paused. 到了楼梯的最上面，她停了下来。

Put your name at the top of each answer sheet. 在每张答卷的顶端写上你的名字。

You can find my address at the top of my letter. 你可以在信头上找到我的地址。

(2)(声音、速度等)达到极限

The baby cried at the top of his lungs. 那婴儿放开嗓门大哭。

He ran at the top of his speed. 他拼命地跑。

(3)(地位、名次等)处于绝对优先或前茅

She came out at the top of the list. 他是名单上名次最高的。

▲on the top of 的用法

on the top of 表示一物在另一物之上。如：

The hill has a tower on top of it. 这山上有座塔。

He balanced the plate on the top of a pile of books. 他把盘子在一摞书上放稳。

They had various knick-knacks on the top of the bookcase. 他们的书柜顶上放有各种小摆设。

▲注意，虽然两者都可表示“在……顶上”，但有区别：at the top of 通常表示顶部或接近顶部的一个相对较大的范围；而 on the top of 则通常指一物在另一物之上。请注意体会以上各例中两者的用法。当然两者的区别有时也并不绝对，比如下面两句，它们的区别就很小：

Her long hair was coiled up in a plait at the top of her head. 她的长发编成辫子盘在头顶上。

You will notice that your baby has two soft areas on the top of his head. 你会注意到你的宝宝头顶上有两处柔软的地方。