释义：
let alone 不值得一提
可以在否定表达后面接 let alone,来说明比前面的内容更差的内容。即 not A... let alone B 中，“B 就甭提了，连 A 也……”。B 的成分可以是动词，... ing 也可以是名词。
例句：
We were barely speaking, let alone having sex.
甭提做爱了，我们连话都不怎么说。
She's not even going to school, let alone not doing homework.
甭提做作业了，她连学校都不怎么去。
She can barely take care of herself, let alone a kid.
甭提小孩了，她连自己都照顾不周。
对话：
A: Is he going to graduate this year?
他今年能毕业吗？
B: He won't pass his classes, let alone graduate.
甭提毕业了，他就连课程也通过不了。
