tenses

The second is correct, the first is not.

InchoateknowledgeThe second is correct, the first is not.

You'll find that many Americans use it.

Actually both are correct.

The first one is an example of what is called a mixed conditional.

The second sentence is the one traditionally taught in most coursebooks.

Contrary to popular belief, their are more than four conditional structures. Mario Rinvolucri, the EFL guru(?), argued that there were over 90 variations of conditional structures in his book Grammar Game

Please explain the meaning

I know what mixed conditionals are, but they not always make sense.

Hello

what is the meaning of the first sentence?:)

If I knew Mary was coming
is in practice used for both present and past times.

If I knew Mary was coming, I would go ot the airport. (present time)
If I knew Mary was coming, I would have gone to the the airport to welcome her. (past time)

The 2nd usage

the first sentence is incoherent.

"If I knew Mary was coming
is in practice used for both present and past times."

distinguished writers insofar as they flagrantly violate established grammatical rules:).

1. If I knew Mary was coming, I would have gone to the the airport to welcome her.

2. If I had known Mary was coming, I would have gone to the the airport to welcome her.

To me, sentence 1 should be:

If I knew Mary was coming, I would go to the the airport to welcome her.

Sentence 2 is correct because o

I know how mixed conditionals work. For instance, I can easily understand and explain this structures

If I had won the lottery, I would be rich

(3rd + 2nd)

and

If I didn't trust her, I wouldn't have told her the whole story

(2nd + 3rd)

But

If I knew Mary was coming, I would have

From the BBC:


BBC NEWS | England | Soldier gun threat 'seen as joke'

He said: "If I knew he was serious I would have gone and