Whose is this handbag?复数 ：Whose are these handbags?
这是谁的手提包?这些手提包是谁的?
应该是：are these your umbrellas?那what colour is your car?的复数形式是什么what colours are your cars?（你的几部车个是什么颜色的意思） 或 what colours are your car？（你的车是些什么颜色？）我觉得都可以，根据具体情况吧There are five girls in the park面对这个回答，应该怎么提问How many girls are there in the park？对数量的提问用how many 和how much那这个回答的提问是什么Look at that car.It's a toyota.Look at that car.What （kind of） car is it？It's a toyota.