Writing Sentences

In English sentences, the form of the verb is partly determined by the subject of that verb, specifically by the person and number of the subject. The following table provides examples of sentences that follow the rules of agreement between subject and verb that are part of normal English usage. You'll see that, basically, verb forms are marked to signal whether their subject is 1st, 2nd or 3rd person, and to signal whether the subject is singular or plural. These are rules that you know quite intimately as a speaker of English; for example, you would never make a mistake in normal speech and say something like 'I is a biologist'.

	Singular	Plural
1st person	I like Biology. I am a biologist. I was a biologist.	We like Biology. We are biologists
2nd person	You like Biology. You are a biologist. You were a biologist.	You like Biology You are biologists. You were biologists.
3rd person	The student likes Biology. He likes Biology She is a biologist. She has studied Biology. He was a biologist Grease has risen to the surface. It has risen to the surface.	The students like Biology They like Biology. They are biologists. They have studied Biology. They were biologists. Some solid materials have risen to the surface. They have risen to the surface.

Notice that the form of the verb in these examples also signals the tense of the verb. ie. the time frame of the action, either past, present or future.