Answer:
He can't open the door; it's stuck.
Step-by-step explanation:
The word "can't" is used in the sentence to indicate that the person is unable to open the door because it's stuck. "Can't" is a contraction of "cannot," and it expresses the idea of incapability or impossibility. In this context, it conveys that the person does not have the ability to open the door due to it being stuck or jammed. The sentence is describing a situation where the action of opening the door is not possible because of an obstacle or mechanical issue.