let alone+动词.怎么用?解释为至于/更不必说..怎么用?

1.Leave alone 防止干搅或干扰
Leave him alone and he will produce.
别打扰他，他会写出来的。
Left alone, he was quite productive.
别打搅他，他相当有创作才能。
2.let alone Not to mention; much less:
更不用提；更别说： “Their ancestors had been dirt poor and never saw royalty, let alone hung around with them”(Garrison Keillor)
“他们的祖先穷得要命，从来没有见过王族成员，更不用说和他们在一起了”(加里森·谢勒)

let it alone!不要管它（别去弄它）
let it alone to do it 让他自己去干吧！
let alone+to be

he cannot speaking Chinese well,let
alone speaking English.