English verb conjugation
In English, all tenses and aspects of a verb can be derived easily from its theme. In the following example, the verb "see" is conjugated on the basis of its theme "see saw seen".
Basic tenses
Simple present (from present tense)
I see
you see
he/she sees
we see
you see
they see
Simple past
I saw
you saw
he/she saw
we saw
you saw
they saw
Past participle
I have seen
you have seen
he/she has seen
we have seen
you have seen
they have seen
Past perfect (from past participle)
I had seen
you had seen
he/she had seen
we had seen
you had seen
they had seen
Passive voice
The passive voice exists in all tenses and is formed from past participle. For example:
English is spoken all over the world.
Other tenses
Present continuous (from present tense)
I am watching
you are watching
he/she is watching
we are watching
you are watching
they are watching
"Watch" is a regular verb. Its theme is formed simply with the -ed suffix: watch watched watched.
Imperative (from present tense)
Come here!
Simple conditional (from present tense)
Tom could come.
Conditional perfect (from past participle)
Tom would have seen the problem immediately, if he had come.
Future (from present tense)
I will see
you will see
he/she will see
we will see
you will see
they will see