Number + 堆 + Noun
堆 (duī) is a measure word (classifier) used for piles, heaps, or mounds of things. It describes a quantity of items gathered together in a pile. For example, 一堆树叶 means 'a pile of leaves.'
地上有一堆脏衣服,你赶紧洗一下。
Dì shàng yǒu yī duī zāng yīfu, nǐ gǎnjǐn xǐ yīxià.
There is a pile of dirty clothes on the floor; hurry up and wash them.
桌子上放着一堆书,都是他买的。
Zhuōzi shàng fàng zhe yī duī shū, dōu shì tā mǎi de.
There is a pile of books on the table; they were all bought by him.
门口有一堆落叶,风一吹就散了。
Ménkǒu yǒu yī duī luòyè, fēng yī chuī jiù sàn le.
There is a pile of fallen leaves at the door; when the wind blows, they scatter.