I'm teaching an ESL class and am having difficulty explaining a concept to my students. Primarily because they like to know the rules and this situation doesn't fit the rule!
A question on their exam is stated: Change the following verbs from simple present to simple past and write a negative sentence using the simple past. The verbs are: have (had), call (called), bring (brought), can (could).
The rule for creating a negative statement in the simple past is to use the auxiliary verb do in its past tense form (did) plus the negative (not) before the simple present of the verb.
ie: I didn't have a new car. She didn't call me. He didn't bring his books to class.
The conundrum is that this scenario doesn't work for can/could. You have to change could to couldn't to make it negative. But then why can't they just change had to hadn't? And furthermore, would the following sentence be negative simple past without following the rule: I hadn't brought anything to the party?
I never realized how confusing English grammar is until I try to explain it to someone else!
This is fine when there is an auxiliary verb: Present Perfect, Past Perfect, and Future Tense are formed using an auxiliary verb.
e.g. I have brought you a cup of tea. (Present Perfect Tense)
But most often, in the Past Tense, there isn't an auxiliary, because Past Tense is a conjugation of the infinitive e.g.
'to sleep' - slept.
So we use 'do/did' as a 'dummy' auxiliary verb.
dummy: something designed to resemble and serve as a substitute for the real or usual one.
But the modal verbs ARE auxiliary verbs, so we don't need to use 'do/did' as a substitute, the 'dummy' auxiliary verb. Otherwise, it would be:
I can play the piano.
I can't play the piano.
I could play the piano.
and from YOUR rule, subject +do+ not + main verb.
I did not could play…
or
I didn't could play the piano.
"would the following sentence be negative simple past without following the rule:
I hadn't brought anything to the party."
No. It's Past Perfect Tense: had not brought.
It wasn't MY rule. I found it on several websites which of course doesn't make it correct.
From http://web2.uvcs.uvic.ca/ELC/STUDYZONE/330/grammar/pastnq.htm:
Negatives in the simple past are formed by adding didn't (informal) or did not (formal) before the simple form of the verb. The verb BE is an exception to this; in the case of BE, we just add n't (informal) or not (formal) after "was" or "were"
Thank you for your response as I'm sure it will come in handy!