Can "would" be used twice in an English conditional sentence and still be grammatical?
Use of deontic would in the protasis and epistemic would in the apodosis:
“If you would all PLEASE take your seats, we would actually be able to get started on time for once.”
Non-native speakers should probably not attempt this.
Explanation
The asker appears to be looking for a counterexample to the simplistic “rule” sometimes taught to English language learners never to put would on both sides of a conditional.
Normally this is true, but you actually can put would in the “if” part not just the “then” part provided that the first one carries the special restricted sense of were willing to or wanted to.
- If only you would write more carefully, you would get higher test scores.
- If only you were willing to write more carefully, you would get higher test scores.
- If only you could write more carefully, you would get higher test scores.
- I would give it a shot if you would like me to.
- I would give it a shot if you wanted me to.
The English modal system is much more flexible and varied than simple “rules” are much good at explaining.
I can think of five hundred ways to destroy him: how I would would not be a problem.
Disclaimer: Not a native speaker.
"Would you ever use would twice in a sentence?"
"I would, but would you?"
The first is mentioned but you could count it as a use. In the second case you could omit the but and have the two words consecutive with only a comma in between.
George and Ira Gershwin have a great example for you:
He'll build a little home
That's meant for two,
From which I'll never roam,
Who would, would you?
And so all else above
I'm dreaming of the man I love.
https://www.youtube.com/watch?v=tGe-i7mRMes&feature=share