The past tense of 'to back' is 'backed'.
Backed is the past participle of back.
The past tense is came back.
The simple past tense is "gave back"
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.
You can't go back to the past.
a past maybe
The past tense is backed.
Got back.
I got back
went back
No. If it is being used as a verb, "back" is the present tense. The past tense would be backed.
Because the main character (Marty) gets trapped in the past and he has to get back to his own time, which is the future from the perspective of the past.