There is not mention of why the writers of Back to the Future II decided not to include Jennifer in the story as a serious character. It most likely had to do with the decided plot.
The infinitive would be "to decide", the present tense would be "decide(s)", and the past tense IS "decided". The word decided is the past tense. The present and future tense are (PRESENT) decides or decide and (FUTURE) will decide.
Watch Appaloosa and decide if you can do what the Ed Harris character decided to do.
The present perfect tense of decide is:I/You/We/They have decided.He/She/It has decided.
Had decided is the past participle.
Had decided is the past participle.
Decide is a verb. past = decided
Decide is a regular verb so you add - ed to make the past and the past participle.decide / decided / decided
the future perfect of "decide" is "have decided".
The past tense of decide is decided.
The correct term is decided to join.
I/You/We/They decide. He/She/It decides. The present participle is deciding.