sentence.

Now, if I write a word over the first line, thus--(doing it)--you will
understand that that word is the subject of a sentence. If I write a word
over the second line, thus--you will understand that that word is the
predicate of a sentence.

Planets | revolve
============|===========
|

The class can see by this picture that _Planets revolve_ is a sentence,
that _planets_ is the subject, and that _revolve_ is the predicate.

These signs, or illustrations, made up of straight lines, we call
+Diagrams+.

+DEFINITION.--A _Diagram_ is a picture of the offices and relations of the
different parts of a sentence+.

_Analyze_ and _diagram_ the following sentences.

1. Waves dash.
2. Kings reign.
3. Fruit ripens.
4. Stars shine.
5. Steel tarnishes.
6. Insects buzz.
7. Paul preached.
8. Poets sing.