Question

【题目】-- Who's trousers are they?
-- They are my sister's.

Answer 1

【答案】Who's错误，改为Whose
【解析】句意：—这是谁的裤子？—是我姐姐的。who's=who is，对人提问。根据回答可知这里是对所属关系题意，该用whose。