it is a man standing

[navi tasan]

Which are correct:

1-It is a not a minor event but a major financial disaster that is happening now.
2-It is a not a minor event but a major financial disaster happening now.
(Meaning: What is happening now is not a minor event but a major financial disaster.)

3-It was not a small animal but a tiger that was in the cage.
4-It was not a small animal but a tigernin the cage.
(Meaning: What was in the cage was not a small animal but a tiger.)

[emsr2d2]

Which are correct:

1-It is a not a minor event but a major financial disaster that is happening now.
2-It is a not a minor event but a major financial disaster happening now.
(Meaning: What is happening now is not a minor event but a major financial disaster.)

3-It was not a small animal but a tiger that was in the cage.
4-It was not a small animal but a tigernin the cage.
(Meaning: What was in the cage was not a small animal but a tiger.)

Remove the first "a" from numbers 1 and 2 and they're OK. None of the four are very natural but they're grammatically correct.

What do they have to do with your thread title though?

[navi tasan]

Thank you emsr2d2.

Nothing! I wanted to include a third example but then deleted it!

A-You thought a woman was at the door, but it was a man standing there.

[emsr2d2]

Thank you emsr2d2.

Nothing! I wanted to include a third example but then deleted it!

A-You thought a woman was at the door, but it was a man standing there.

That sentence is fine. For future reference though, it's much more helpful for us if you make your thread title relevant to the contents of the post. Thanks.