偶是英语初学者.不懂!It is an old backpack 复数形式的是：These are old backpancks.还是They are old backpacks..还有,They 后边为什么是原型呢?那个They are old backpanck用不用加S?
网友回答
It is an old backpack 意思是 它是一个旧的双肩背包.要复数的话就要他们是旧的双肩背包.也就是They are old backpacks..（backpack 是可数名词,所以要+s）、如果是These are old backpancks.那么意思是,这里有旧的双肩背包.backpack在初中英语书是双肩背包的意思,