'd instead of would - when is it acceptable? [closed]

I am a teacher of English as a second language (secondary school). I've been correcting a test on the 3rd conditional - the task was to change the given sentences from a 2nd conditional form to a 3rd conditional one - and many students wrote the following: 1) The manager'd pay high salaries if more profits were made.

I want to point out to them that they should have written the complete form "The manager would pay high salaries ... " instead of the abbreviation "'d", but I don't know how to explain the grammatical reason why. I just know (or feel) it's wrong, but I need to provide an adequate explanation.

I agree with you that the students should be encouraged not to use the contraction in this sentence.

The reason I would give is that people would have trouble understanding them if they used a contraction here.

Contractions of would are clearly understandable with the pronouns (e.g. he'd, she'd we'd, etc., but with less common uses, the listener would have to work too hard to understand. If you try speaking this sentence out loud, you'll see what I mean. Manager'd sounds like manager is a verb and we put it in the past tense. Which doesn't make sense in this context -- so then the listener has to play it back in his mind and re-parse it. Rule #1 in communicating in a non-native language: make it easy for your listener to understand you.

(Such a contraction would only be used in written English if one were writing dialogue or writing something that evokes spoken English.)