第一， 情景对话

A: Bob, can you tell me how many students passed the college entrance examination this year?

鲍伯，你能告诉我今年有多少人考上大学了吗？

B: Off the top of my head, I'm afraid I don't know.

不查的话，我也搞不明白。

A: Never mind. Well, can you tell me where I can get the information?

不要紧，你知道从哪里能查到有关的信息吗？

B: Maybe from the Education Daily.

《教育报》上也许会有。

第二， 词海拾贝

off the top of one’s head

exp. From memory or without much or careful consideration. （不假思索地，信口开河地）

e.g. She answered the teacher's question off the top of her head.

她随口回答了老师的问题。

e.g. John can list the capital cities of all 50 states off the top of his head.

约翰能不假思索地列出所有50个州的首府城市。

e.g. Mary: How much do you think this car would be worth on a trade?

你认为这辆车在市场上买多少钱？

Fred: Well, right off the top of my head, I'd say about a thousand.

嗯，不看汽车行情资料的话，我觉得大概一千元。