Final -ed: Avoiding Incorrect -ed Endings
Do not add -ed to any verb form that immediately follows the word to.
In the first set of two sentences above, climbed and looked are verbs. In the second set of sentences, to climb and to look are infinitives and therefore have no -ed endings.
Gordon climbed the ladder.
He looked in the window.
Gordon hurried to climb the ladder.
He tried to look in the window.
Do not add -ed to the first verb that follows any auxiliary other than to be or to have.
In the first set of two sentences above, sprayed and slowed are single-word verbs. In the second set of sentences, spray and slow are main verbs following an auxiliary other than to be or to have. Here is a list of the auxiliaries that must be followed by a base form:
We sprayed for cockroaches today.
We slowed down the invasion.
We should spray for cockroaches today.
We might slow down the invasion.
- will, shall
- can, could
- would, should
- may, might, must
- do, does, did