They need some red hats(对some red hats 提问) ____ ____ they____?
问题描述：
They need some red hats(对some red hats 提问) ____ ____ they____?
答
What colors of hats do they need？
What colors of hats就是一个整体！正好满足几个格子，同时也是对some red hats 提问
答
What do they need?
答
They need some red hats(对some red hats 提问) ____What ____do they____need?
答
What do ... need
对“物”提问，用what
答
some red hats 是物品,所以用what提问：
What do they need?
他们需要什么?
They need some red hats.
他们需要一些红帽子.
答
正确：What do；need