Set 1 verbs indicate that the perceiver is “focusing” on a specific object. They can be used in the progressive.
He is listening to the radio.
They are looking at the picture.
She is smelling the flowers.
Set 2 verbs indicate general perception and are non-progressive.
He hears a noise.
They see flames.
She smells smoke.
|(Not: He is hearing…)
(Not: They are seeing...)
Set 3 verbs indicate appearance. (It “seems”…) They are non-progressive.
That sounds like thunder.
This looks terrible.
It smells fishy.
|(describes the object, not the perceiver)
*When feel is used to describe emotions, the progressive is sometimes used.
I feel great today.
I feel cold today.
|I am feeling great today.
(physical feeling is usually non-progressive)
*See can sometimes be used in expressions in the progressive.
Special Usage of Certain Verbs of Perception
Some verbs of perception see, look at, hear, listen to, and feel, along with watch and sense can be used with objects followed by other verbs (base form or gerunds, but not infinitives).
Note the examples below:
We heard you leave. (Okay. Emphasis on our hearing.)
We heard you leaving. (Okay. Emphasis on your leaving.)
We heard you to leave. (Incorrect!)
I saw her go.
Look at that man run!
Sylvesterlistened to the canary sing.
We watched them play basketball.
We watched them playing basketball.
Trudy can feel the wind blowing against her skin.
Mr. Todd sensed the lion approaching.