基本用法 If places alike, there would be little need for geographers A being B are C be (were If we had known (know) that the books were available, we would have bought them yesterday基本用法 • If places ____ alike, there would be little need for geographers. • A. being B. are C. be D. were • If we _________ (know) that the books were available, we would have bought them yesterday. had known