to fall down · to slip and fall · to throw sb to the ground

As Ziri ran out of the classroom, he bumped into someone and fell to the floor.

Tom fell down.

Tanina fell.

I tripped in the alleyway in the darkness, as I crashed my knees on the asphalt. There was a wooden board that covered a wire between houses across the alleyway. It was very dark there at night. My eyeglasses fell off my face. Luckily, a Cantonese labourer with a flashlight helped me. My knees just got scraped. I remember another time when I crashed on my knees. It was at Don José Heights in Quezon City in the Philippines. There was a vastness of Martianesque red soil, wherein the "talahib" grass grew. Sometimes, workers intentionally set the grass on fire. My brother and I were still playing, even then, outside. We were still prepubescent. Near burning grass, I stumbled on my knees. My grandmother, Lola Bebe, was so angry. A maid washed my legs in the big tiled sink behind the garage.

Tom fell into a vat of sulfuric acid.