题目

Those socks_______ white, but this pair of socks_______ black. A . is; is B . is; are C . are; is D . are; are 答案：C要鉴别由不锈钢和塑料制成的外形完全相同的两个汤勺。（1）方法一：_____________________ ，利用了________ 属性；（2）方法二：______________________，利用了________ 属性。