At no time
did the company break the law.
Compare:
The company did not break the law at any time.
Under no circumstances
should you travel alone.
Compare:
You should not travel alone under any circumstances.
Never in my life
have I seen such extraordinary behaviour.
Compare:
I have never seen such extraordinary behaviour in my life.
The telephone had been disconnected. Nor was there any electricity.
Compare:
There wasn't any electricity either.
Seldom
did we have any time to ourselves.
Compare:
We seldom had any time to ourselves.
Only in summer
is it hot enough to sit outside.
Compare: It's only hot enough to sit outside in summer.