not to mention/let alone

not to mention 与 let alone 虽然都是准并列连词,但是它们有一个很重要的区别:not to mention 的后面只能接名词短语,而 let alone 后面可以接任何词性的词项,并且大都用于否定句之后。请考察下面的例句:

1. He rejected it for its cost, not to mention its ugliness. (MED) 他因为价格高而没买它，更不用说它很难看了。

2. He wrote twenty novels, not to mention six thick volumes of verse. (CGEL) 他写了二十本小说,更不用说六厚本诗集了。

3. We're too busy to take a long holiday this year, not to mention the fact that we can't afford it. (ALD) 我们太忙，今年不能去度长假，更不必说我们拿不出这笔费用了。

4. They own two houses, not to mention a boat. (《韦氏词典》, 电子版) 他们拥有两栋房子, 更不用说还有一只船。

5. Dave is handsome and smart, not to mention being a good athlete. (DAI) 戴夫漂亮而聪明,更不用说还是个好运动员。

6. I had never seen him, let alone spoken to him. (let alone 连接谓语的一部分 spoken, 其他例句, 见 not to say/let alone) 我从来没见过他, 更别说与他交谈了。

7. She will not help her brother, let alone a stranger. (ELD) 她连自己的弟弟都不愿意帮助，更不用说陌生人了。