And yet that's precisely how it is in most teaching of grammar.
There is a standard notation for showing sentence structure - in fact, there are dozens of them, and the only problem is to choose the most useful one.
Here's a good one that was developed for French schools, and which is now being taught to Danish children. You can see how a computer applies it at www.visl.hum.sdu.dkvisl - this is a good way to learn, but you'll soon get better than the computer.
The idea of this notation is to show how words fit together by treating the whole sentence as an expansion of its verb. Regular readers will remember our little fable about the grammatical squirarchy, where the verb is boss and the subject and object are its chief servants. Naturally enough, we write the verb above the other parts of the sentence, like this: Why stop there? We can do the same to the smaller phrases, showing how each phrase is an expansion of one of its words. This takes us deeper and deeper into the sentence's anatomy. What emerges is the sentence's skeleton, the scaffold of relations that hold the words together. Here it is: One of the many uses of sentence diagrams is in discussing ambiguities. For example, you can lay out the options for "I sent the letter to Mary", showing how "to Mary" could modify either "letter" or "sent".
Or you can use them like "mind-maps", as a way of exploring different ways of modifying a given word.
One of the reasons we think this is useful is because people learn in different ways. Traditionally, we've tended to teach grammar through words, and yet for visual learners a diagram or map might better help them to understand sentence structures. At the very least it gives a new insight into ways of demonstrating language features.
Richard Hudson is professor of linguistics at University College, London Geoff Barton is headteacher of King Edward VI School, Bury St Edmunds, Suffolk