Grammar question

[rico4444]

I am quite familiar with causative verbs but I came upon a sentence that I cannot explain. "I saw my mother park the car." "Saw" is not a causative verb. "Mother" is the D.O. What is "park?" What is the rule that says we can use an infinitive form without the "to" if it is not a causative verb?

[Humble]

Hi, Rico,
Welcome to the forum.
The construction is called Complex Object.
I felt her hand touch my hair.
She heard him open the door.
After verbs of perception the infinitive goes bare.
After others, with to.
We expect them to arrive at noon.
Baby, I'd love you to want me.

Best wishes.

[Belly T]

Yes, "saw" is not a causative verb but perception verb. it's the past tense of "see". The structures follow after perception verb are:
P.V+ V-ing express you only know a part of action
Ex: We saw her going down the stair

P.V+ V-bare: You know the whole action
Ex: We saw her go down the stair

'Park" means to leave a vehicle that you are driving in a particular place for a period of time