We can use either the infinitive withouttoor the -ingform after the object of verbs such ashear, see, notice, watch. The infinitive withouttooften emphasises the whole action or event which someone hears or sees. The -ingformusually emphasises an action or event which is in progress or not yet completed.
| The speaker observed the whole event. |
| The action was in progress, happening, but not completed. |
The -ingform can also emphasise that an action or event is repeated:
Wewatchedthemrunningback and forth,loadingandunloadingthe trucks andtakingboxes in and out of the building.
Aftercanorcouldwith one of these verbs, we always use the-ingform, not the infinitive:
Ican hearpeopletalking. They must be in the next room.
Not:I can hear people to talk.
Typical errors
We don’t usetowith the infinitive form after the object:
Sheheardthe doorbellringand went to answer it.
Not:She heard the doorbell to ring…
We don’t use a finite verb form after the object:
Iwatchedthe womancomeout of the house andgetinto a car.
Not:I watched the woman came out of the house and got into a car.