I need a swimming suit.(对划线部分提问)

问题描述:

I need a swimming suit.(对划线部分提问)

线在哪?

对a swimming suit划线提问,为:What do you need?
对a提问,为:How many swimming suits do you need?
对I提问,则为:Who needs a swimming suit?
估计是第一种情况,楼主最好要讲明是对哪部分划线提问.