'simple past tense'
Simple past tense indicates an action completed in the past.
Time adverbs are content words which add meaningful content to a sentence.
Context, sometimes, gives us the meaning.
E.g.: I didn't sleep.
Presumption: yesterday night.
Clearer: I did not sleep last night.
Clearer: I did not sleep during duty hours, through out my service.
Acceptable: We fought for our independence.
Presumption: Can't presume when the fight took place.
Clearer: We fought for our independence in 1776.
Alternate: We can, probably, use a past perfect form, if the time is not important.
We had fought for our independence.
We can use a manner adverb, if the manner is more impotant:
We had (valiantly) fought (valiantly) for our independence (valiantly).
We can add m-adverb and t-adverb, if both are important:
We (valiantly) fought (valiantly) for our independence (valiantly) in 1776.