What are the grammatical rules determining whether to use “which” or “what”?

What are the grammatical rules determining whether to use which or what? I usually go by intuition. It’s “What car are you looking at?” and “What bicycle do you like most?” but “Which song did you sing?” Quite often, I don’t know whether to use what or which. How can I tell? Answer Which is … Read more

Is there any difference between “which” and “that”?

What is the difference between the words which and that? For example I have the following sentences: “I have a car which is blue.” “I have a car that is blue.” Are there any rules specifying usage of which and that? Answer There is no difference in meaning. There is a difference in use. Relative … Read more