Usage of lest
how to use "lest"? I suppose it's somehow close either to "unless" or "not to", albeit I'm not sure if conditionals are allowed to be used as well, moreover, I guess, lest implies negative sense if there are positive sentences and vice versa.

do not pull the lever, lest she's crumbled up by the saw(if she was captured by a maniac and her body was seized and stuck between a wall and the well-hung saw)

if I hadn't picked the successive point of that agenda lest I had been impeached and deprived from social perks such as my own yacht and the most contemporary model of "Ford" cars, I wouldn't be inmate now.

I called her immediately lest she would know about his yesterday's sins at the enjoying party
if you had printed out those memos ,lest I had been suspended and not lost my high social status, I would've approved of your idea in state duma

Question

Usage of lest
how to use "lest"? I suppose it's somehow close either to "unless" or "not to", albeit I'm not sure if conditionals are allowed to be used as well, moreover, I guess, lest implies negative sense if there are positive sentences and vice versa.

do not pull the lever, lest she's crumbled up by the saw(if she was captured by a maniac and her body was seized and stuck between a wall and the well-hung saw)

if I hadn't picked the successive point of that agenda lest I had been impeached and deprived from social perks such as my own yacht and the most contemporary model of "Ford" cars, I wouldn't be inmate now.

I called her immediately lest she would know about his yesterday's sins at the enjoying party
if you had printed out those memos ,lest I had been suspended and not lost my high social status, I would've approved of your idea in state duma

Answer

I live in England and it is very rarely used in conversation, perhaps slightly more so in written language, but even then, very rarely. In England it is most commonly associated with ‘Lest we forget.’ which is a phrase used to commemorate those who died in the first and second world wars.

Answer

@oliver, reread sentences above

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Can you give an example of how you’d like to use it?

It isn’t common in American English. In fact I’d say it’s less common in American English than in British or other international English dialects. However I’ll defer to the Americans here on this question.

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Btw is it common in american english?

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I had known it till your replies and, moreover, I'm preparing to compose a scientific article about a law issue. I just need an elaboration on whether it's allowed to use lest with conditionals. I'm asking it as I've heard lest isn't supposed to be used with will and would