I can't understand how some of the relative clauses work in English. I see no difference between the two given examples:
Barbara works for a company...
Colin told me about his new job...
a company/new job
What's the difference? Why can't we use that in the second sentence? I think they both give some extra information, not just the second one. But they say we can use which in the first one. If so, why don't they put a comma before it?
All the explanations I read on the topic are not clear and do not tell the difference.
There's another sentence that/which (???) I found on the web:
The iPad (which/that) connects to the iCloud was created by Apple.
The correct answer is: The iPad, which connects to the iCloud, was created by Apple. (All iPads connect to the iCloud, so it's unnecessary information.)
If we use that, does it mean there are other iPads that/which (???) were created by other companies (but we know that all iPads are made by Apple — there's only one iPad that/which (???) is created by Apple)?
This is so confusing. I also put that/which clauses in bold that I don't know the correct answer for (I hope some of them are interchangeable).