VERBS OF PERCEPTION are verbs that explain how we use our bodies to know about the world. They explain how we use our "five senses". These are our senses of:
- touch, taste, sight, hearing and smell
Example verbs are:
- hear, listen, see, watch, look, taste, feel, sense
They also include some mental processes we have when we sense things. For example:
Verbs of Perception often take an infinitive clause with a verb in the 'infinitive', or plain form:
- Tom heard her shout his name.
- I witnessed her leave the building.
- We saw Bob eat the pie.
- I felt the atmosphere lighten.
- Look at them run.
- I will watch the sun rise again.
Notice that the pronouns before the verbs are always accusative ( - we use him not he, for example). The verb in the subordinate clause has no tense. The verb in the main clause carries the tense:
When the verb is in the plain form like this, it means that we sensed the whole action. We saw (or heard, etc) that the action was completed. Importantly, we also sensed it while it was happening.
However, sometimes we only see part of the action. We may not see whether the action was completed, but we saw somebody or something while they were doing the action. In one of the examples above we saw Bob eat the pie. This means that we saw him eat the whole pie. He finished it. If we only see part of the action we can use a Verb of Perception with a verb in the --ing form:
- We saw Bob eating the pie.
In the example above, maybe we only saw Bob eating for a very short time. Maybe a few seconds. Perhaps Bob didn't finish eating the pie. Perhaps he did. The sentence does not give us this information. It emphasises that we saw Bob during the eating process, and it emphasises the eating action, not its completion.
The verb SEE
Sometimes we use the verb SEE with a different meaning. It means something like understood or noticed. When we use it like this it can take a finite clause - a clause with a tensed verb. The finite clause will often use the word that:
- I saw that Bob had eaten the pie.
This meaning of SEE is a bit different from in the examples further above. When SEE takes a finite clause like this, it doesn't mean that we actually saw the action. It just means that we saw something which made us know that the action happened. In this example, maybe we saw Bob with the pie in front of him. Later we saw him with an empty plate, and the pie was gone. We didn't see the eating action. But we understood that Bob had eaten the pie because we got the information from other things that we saw.
We can only do this with some Verbs of Perception, such as SEE, NOTICE or OBSERVE. If we use a Verb of Perception with a verb in the plain form or --ing form, then it means we actually sensed the action while it was happening.
The Original Poster's example
Gordon was about to walk away from the Impala when he saw it stop and his son get out.
In the example above Gordon actually saw the actions. The actions were:
- The impala stopped.
- His son got out of the vehicle.
Gordon saw these actions happening, and he saw them finish. The actions were completed whilst Gordon was watching them. Because of this, the verbs in the subordinate verb phrases are in the plain form. They have no tense. We understand when the actions happened, because the Verb of Perception, saw, has past tense. The actions happened at the same time as the "seeing".
The verb saw takes a coordinated complement here:
- he saw [ it stop ] and [ his son get out ].
The two clauses in brackets, [ ], show what Gordon saw. We do not need to use the verb saw twice. The parts in brackets both function as the complement of saw. The word and shows that they are 'coordinated'.
Hope this is helpful!