▲个人觉得，句中的 not 其实是用于否定后面介词短语 on account of the fact that t I was a bricklayer 的，只不过被句中的 I hasten to add 隔开罢了。句子意思应该是：她没有接受我的求婚——我急忙说明一下，不是因为我是个砌砖工。

▲体会以下相关句子中 not 的用法：

1. The deal with Chelsea may not, however, be dead. 不过，与切尔西的交易或许还有戏。

2. He could not, after all, stop all the evil in the world. 毕竟他无法阻止世界上的所有恶行。

3. He had not, until recently, stooped to personal abuse. 他以前从未像最近这样卑鄙到进行人身攻击。

4. He is popular among men, though not, perhaps, with ladies. 他很受男士们的欢迎，虽然也许不一定讨女士们的喜欢。

5. I would not, if I were you, be inclined to discuss private business with the landlady. 我要是你，就不会跟房东太太谈私事。

6. Could he not, just as a precaution, move to a place of safety? 就算仅仅是为了以防万一，难道他就不能挪到安全的地方吗？

7. Encouraging teacher transfer would not, by itself, integrate the teaching corps. 鼓励教师调动本身不会消弭教学队伍中的种族隔离。