If you can't, use that A which clause goes inside commas, a that clause doesn't. Now let's put the rules to work. The dog that won best in show was Buster's bulldog. The point of each sentence is that Buster's dog won.
Some people consider which more refined or elegant than that .
In fact, that is more likely to be grammatically correct than which . That's because most of us don't put unessential information in the middle of our sentences, especially when speaking.