Contract Law Simplified: Conditions

I'm wondering if you can give an example of a promissory condition?

Also, I'm wondering why the condition in Jacob & Young v Kent was not an explicit condition or term?

Thank you so much!

Where a conditional offer is made - is it right that is the condition is "condition precedent", then the contract is void until the condition is met (regardless of whether the offeree has accepted it previously). Also, if the condition is "condition subsequent", then the contract is 'voidable' when the condition fails to be met.

When analyzing whether a term is a condition, promise, or promissory condition. Can you give some common examples of conditional language? I would imagine it would be "conditioned upon..." or "if...then". Do you have any other common language examples that appear within clauses that reference express conditions?

Thanks for the helpful video!

Is de minimus rule applicable to "substantial performance"? Thanks.

Can I understand as:
Part performance vs complete performance -->substantial performance triggers mutually at implied term
Promise vs condition --> condition precedent as an on switch at beginning --> condition subsequent as an off switch at beginning
Mutuality -->implied promise in return for promise