The past tense of 'to back' is 'backed'.
The past participle of "back" is "backed."
The past tense is came back.
The simple past tense is "gave back"
You can't go back to the past.
a past maybe
The past tense is backed.
called back.Call back is a phrasal verb. When changing to past only the form of the verb call changes. The adverb back remians the same.
Got back.
went back
I got back
No. If it is being used as a verb, "back" is the present tense. The past tense would be backed.
Another way to say "back then" is "in the past" or "in earlier times."