In the reading sentence 'Who was the first President?', the word 'Who' is used to ask about:

On the USCIS reading test, the question word 'Who' is used to ask about a person. In the sentence 'Who was the first President?', 'Who' signals that the answer is a person (George Washington). The reading vocabulary's question words each point to a type of answer: 'Who' asks about a person, 'Where' about a place, 'When' about a time, and 'Why' about a reason. Recognizing what each question word is asking helps the applicant read and understand the sentence. This comprehension of question words is part of the reading-test skills.