Dear ATEGgers, To me, the grammatical difference between which and as is that basically which refers to a noun, while as refers to a verb. Of course they expand their reference. When the reference to a verb is synonymous to reference to the verb and its object, either works. But: He has a terrier, as his neighbor has. They both have terriers. He has a terrier, which his neighbor has. The neighbor is keeping the dog while the owner is on vacation. Then when you get to adjectives: He is busy, as was expected. As refers to is busy. He is busy, which was expected. Busy is assumed to mean a busy person, I guess, or it could refer to the whole clause, that he is busy.. Anybody have a better answer to an interesting question? Carolyn Hartnett [log in to unmask]