I know that present simple tense may serve to inform on present habits. Could anyone explain how to proceed when we talk about the past? How about the negative sentences in such cases? Is the following sentence correct:
'The documents used not to be supplemented'.
If so, is a contraction 'usedn't' correct?
"used to" is a good way to talk about past habits, and, yes, it can be used in the negative ("used not to") in the way that you illustrate. I do not recommend the contraction "usedn't". The negative form "didn't use to" is sometimes used colloquially, but in my view this is inferior to "used not to", and in particular should be avoided in careful writing.
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"used to" is a good way to talk about past habits, and, yes, it can be used in the negative ("used not to") in the way that you illustrate. I do not recommend the contraction "usedn't".
The negative form "didn't use to" is sometimes used colloquially, but in my view this is inferior to "used not to", and in particular should be avoided in careful writing.