That and which

[AllFallDown]

I am very concerned that some posters here have trouble differentiating between that and which. Further offences will see you banished to Countdown's dictionary corner.
Here is a handy definition from a reputable reference source:

"That" defines, "which" gives extra information (often in a clause enclosed by commas):
This the house that Jack built, but this house, which John built, is falling down.
Note that the sentence remains grammatical without "that", but not without "which".

Thank you very much for the explanation which you have given. I mean that you have given... aaaaah!

Ahh you have helped me with that preposition which i can never use correctly

You're all a coven of whiches.

When I began using a computer at work, I used to amuse myself by turning on the grammar check function. As you do.

I can still clearly remember being confronted by a message advising me that "That is almost always preferred to Which in this situation". I learned a good deal from that word processor programme!

... as we fogive themn that trespass against us ...

0h, my typing, should be .... as we forgive them that trespass against us ....