the (red) bag is Amy sister's.(对划线部分提问)

the (red) bag is Amy sister's.(对划线部分提问)
答案是:which bag is Amy sister's?
为什么用which bag提问，划线部分是red对颜色提问不是用What color?
不好意思，请详细点回答，谢谢

The gerl has a {red} bag .对括号部分提问 改错1.The red bag is cheapest of all the bags. 2.Let's leave school at five ten in Saturday. there( )money in the bag. The man held out bag He put it in the the bag. the cat out of the bag The Red的资料 韩国组合THE RED 什么叫the red 韩国组合the red