Questions about the subject of a sentence

1. Questions about the Subject of a Sentence. (verb to be)
George Washington was the first president of the U.S.

Example:
Question: Who was the first president of the U.S.?
Short Answer: George Washington was.

Note: When you ask the question, you don't know the answer. Use the singular was in the question even if the answer is in the plural.

Example:
Mary and Adolf were absent from class two weeks ago.
Question: Who was absent from class two weeks ago?
Short Answer: Mary and Adolf were.

2. Questions about the Subject of a Sentence. (other verbs)
Anita spoke to me in French .

Example:

Question: Who spoke to you in French ?
Short Answer: Anita did.

3. A thing can also be subject of a sentence.
The earthquake caused the destruction.

Example: What caused the destruction?
Short Answer: The earthquake did.