on no account绝不;切勿；
当否定词或具有否定意义的词组如：on no account等位于句首时，在正式语体里，必须采用主谓倒装的语序，即助动词+主语+实义动词：
如：
On no account should the mixture boil.
切勿让这种混合物沸腾。
On no account should we discard our fine traditions and styles of work.
好传统、好作风绝不能扔掉。
When asked for your views about your current job, on no account must you be negative.
当你被问及对目前工作的看法时，绝不要表现得消极。
We must always go into the whys and wherefores of anything. On no account should we follow anyone like sheep.
我们对任何事情都要问一个为什么，绝对不应盲从任何人。
On no account must you accept any money if he offers you.
如果他给你钱你绝不要接受。
On no account must you tell him.
你决不可以告诉他。
On no account should the house be left unlocked.
离开房子时千万要锁门。
On no account must we be impatient.
无论如何不能急躁。
On no account may reference books be removed from the library.
参考书绝对不能从图书馆带走。
On no account should any money be given to a small child.
绝不能给小孩子钱。
类似用法的词组还有：not，no ，never，hardly ,under no circumstance ,not until, not always, in no circumstance , no longer, little，few, seldom, rarely，scarcely ，nowhere ，by no means，not only，not until，at no time, under/in no circumstances，in no respect, in no sense, no less, no more，in vain, still less ，in no case，in no way, no sooner，hardly，scarcely ,neither, nor等。