We slid down the slope.
He slid on the icy sidewalk and nearly fell.
slid is the past tense
The preposition is "down." The phrase "down the banister" modifies the verb slid.
His fingers slid through her silken hair She dabbed her eyes with a silken handkerchief.
Many words do! Here are a couple: bid, kid, pit, kit, kin, fin, tin, live, give, and dinner
slid The car has slid off the road.
slid
The shelf was askew, so the frame slid off.
She slid down the roof, but was stopped by the parapet and did not fall to the ground.
The sailor slid down the rope as though he'd done it all his life.
slid is the past tense
His glasses slid down the ridge of his nose. I'll walk the ridge line today.
The preposition is "down." The phrase "down the banister" modifies the verb slid.
Going around the corner, Jo's car hit a patch of ice, lost traction, and slid sideways into a wall.
The tack slid painfully in to my foot when I stepped on it by accident.
The serial rapist put the canvas bag over the girls head as he slid closed the door of his white E-350 cargo.
She slid down, quickly engulfed by the depths of the river.
The lumbering giant almost grabbed Jack, but he slid down the beanstalk.