Why does it use 'would have'?

Question

Holding hands, people jumped in the water, and floated around in Boston’s Charles River recently. That is something that would not have been possible years ago because the river was so polluted.

Why does it use '...would have...' instead of 'was not possible...'?

thanks

Possible duplicate of Are there any simple rules for choosing the definite vs. indefinite (vs. none) article? — 325newton, Sep 13 '17 at 11:48
If someone had thought of jumping into the Charles River twenty years ago, they would have decided that it was impossible. — Kate Bunting, Sep 13 '17 at 15:07

score 1 · Answer 1 · answered Sep 13 '17 at 18:17

It's the conditional -- that's why you use "would have." The thing did not actually happen; it's a speculation or a proposition -- an "if" statement. As in: If this had happened years ago, X would have been the case.

The grammatical explanation or description for the conditional is

modal [would] + present tense of to have + past participle of the verb

Why does it use 'would have'?

1 Answers1