Learnt and learned are both used as the past participle and past tense of the verb to learn. Learned is the generally accepted way of spelling it in the United States and Canada, while the rest of the English-speaking world seems to prefer learnt for now. ... Soon learned might be the most common form everywhere.

What tense is would have been?

Conditional Tense: What Would Have Been.

Which tense to use with would have?

When to use “Would Have”

“Would have” without a past participle (see below) is simply the conditional tense, plus the verb “to have.” It is used to express an unreal or untrue idea, that would or could be true if something else were true.