In Portal, the Companion Cube's ARE sentient.

The statement "In Portal, the companion cubes are sentient" is true because in the video game Portal, the companion cubes are depicted as having consciousness or awareness. They actively respond to the player's actions and interactions, displaying signs of intelligence, emotions, and a desire for camaraderie. This is evident through their ability to communicate with the player, even though it is through subtle cues such as blinking lights and a distinct sound signature. The companion cubes also display a limited degree of self-preservation and the ability to aid the player in solving puzzles, further supporting their sentient nature within the game's narrative.