Return to the magnet board at the beginning of this chapter. As you were arranging your sentence, which words did you try to use as subjects? Did any of those words eventually get used in some other sentence role? How many different subject and verb combinations did the answer sentence contain?
Obviously, a sentence is more than just a collection of words. The way the words relate to each other is what allows you to create and convey meaning in language. The primary structural relationships within an English sentence are those among subject, verb, completer, and modifier. Once you've got those under control, you can make an infinite number of combinations, communicating and inventing a lifetime of ideas.