Whoa, I’m chiming in a bit late on this one. Several points to consider:
- I totally disagree that the Longman example is poor grammar. “I saw the car, which was very fortunate.”
Now, your contention is that the clause only refers to the car. The clause following the comma can refer to part or the whole of the sentence preceding it. It’s not the car that is fortunate; it’s the seeing of the car that is fortunate. There is no need to recast the sentence. Are you telling me that there is a chance for confusion? Only if one if being deliberately obtuse can one misunderstand this sentence. There is no ambiguity, no confustion, and therefore no need to change this sentence. To my ear it sounds fine, to my eyes it reads fine, so why mess with it?
- “That” vs “Which.” I don’t have the Chicago Manual of Style on me at the moment, but I will say this. Traditionally, as has been said, “that” is used for essential clauses and “which” for non-essential clauses. However, in essential (aka restrictive) clauses, either “that” or “which” can be used. If you don’t believe me, check Chicago Style, because I’m positive this is the case. AP Style keeps the “that” and “which” distinction. Chicago Style does not for restrictive clauses. In other words:
“Get the report that is on the shelf.”
and
“Get the report which is on the shelf.”
Have the same meaning. (Get the report that is on the shelf, not the one that is on the table.)
“Get the report, which is on the shelf.”
This sentence has a different meaning. (Get the report. It’s on the shelf.)
The punctuation does dictate the meaning in this case.
However, I would NOT use:
“Get the report, that is on the shelf.”
I would never use “that” for non-essential clauses. It looks bad; it sounds bad; I would never even say it. The other one is perfectly fine. I’ve never heard “that” in speech used to introduce non-essential clauses, whereas “which” can introduce both essential and non-essential clauses in written and spoken English, with the punctuation provided the correct meaning.
They agree with the basic rule of “that” vs “which,” but admit that “which” used restrictively sans commas is kosher.