Written by 
These two verbs SEE and HEAR enable us to ‘see’ and ‘hear’ without ‘our own volition’…
The reception of the sensory message is involuntary… After that involuntary reception, if
ever we want or need it, then, we can ‘look’ or/ and ‘listen’ with more or less attention,
depending on our interests…
Let’s be careful when we want to use these verbs; they have different constructions. 
SEE and HEAR are two ‘non-Volitional’ verbs (you receive the sensory input without
having to try to.)
These verbs have two different constructions of their DOC (direct object complement).
1) SEE and HEAR may be followed by a DOC + bare infinitive.
– She saw him get off the train and waved at him.
Hear a bee cough …hear you cry
This construction is used when the subject sees or hears the action totally.
The subject has seen the man and waved at him. The two actions were seen
totally, from beginning to end.
2) SEE and HEAR + V + ING:
– I heard her going up the stairs.
That construction in V+ing is used when the subject was seen doing the action.
It had already started and went on till its completion.
The subject was caught red-handed!
She was going up the stairs…
This construction may also stress the fact that the action was long…
That was quick and easy, wasn’t it? Now, go for the test! 
End of the free exercise to learn English: To see and to hear + ing/ bare infinitive
A free English exercise to learn English.
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