See/hear + object + verb form

Definition

Perception verbs such as see, hear, watch, feel, and notice can be followed by an object and either a bare infinitive or an -ing form. The bare infinitive often presents a complete event, while the -ing form presents an action in progress or only part of it.

Examples

• I saw Leo cross the street.

  The bare infinitive presents the crossing as a complete event.

• I saw Leo crossing the street.

  The -ing form presents the action while it was in progress.

• We heard someone knock on the door.

  The bare infinitive presents the complete knocking event.

Complete event vs. action in progress

The distinction is aspectual rather than simply a difference between correct and incorrect forms.

The passive pattern uses to

When the perception construction becomes passive, the bare infinitive normally changes to to + base verb. An -ing complement can remain after the passive perception verb.

• Leo was seen to leave the building.

  The active saw Leo leave becomes passive Leo was seen to leave.

• Leo was seen leaving the building.

  The passive retains the -ing form for an action viewed in progress.

Common mistakes