That Vs which

Could you show some sentences so that they can help you?

Is it "the house that we saw yesterday was Mary's" or "the house which we saw yesterday was Mary's"?

Both are fine because they are defining relative clauses.

Are you asking about restrictive (defining) and nonrestrictive (non-defining) clauses?
See this article:
http://www.englisch-hilfen.de/en/grammar/relative_clauses.htm

Is there any difference in meaning in the above sentences?

fatimah0786Is there any difference in meaning in the above sentences?

Is it "the house that we saw yesterday was Mary's" or "the house which we saw yesterday was Mary's"?

It depends on if your critic is a stickler for precise grammar. Generally in American English, both are accepted without any issues. But the British seem to have higher standards and

If that's the case why is "that" grammatically correct and "which" isn't?

Both words would be understood, and are not likely to be questioned in conversation. I have a preference for using "that" in this case, because you are distinguishing Mary's house from a defined class. If the general class is defined, and you do not have a restrictive adjectival clause that can be separated by a comma, then don't use which. Which is usually preceded by a comma, and that is not

fatimah0786Is it "the house that we saw yesterday was Mary's" or "the house which we saw yesterday was Mary's"?

It doesn't matter. Both are correct.

"which" is a little more formal, I'd say, so I think most people would use "that" in everyday conversation.

CJ

You could also say The house we saw yesterday was Mary’s.