The doorkeeper greeted everyone with a smile.

She stood in the doorway, waving goodbye.

I live in a dormitory on campus.

I lived in a dormitory during my college years.

The doctor prescribed a dose of medication for the patient.

I've reserved a double.

He paid double fare.

She was doubly excited to receive two presents.

I have a doubt about the answer.

I am doubtful about his intentions.