Numeral + 匹 + 马
The noun 马 (mǎ) means "horse" and refers to the animal used historically for transportation and labor. It appears in many common compounds and idioms in Chinese.
那匹马跑得真快。
nà pǐ mǎ pǎo de zhēn kuài.
That horse runs really fast.
小时候我骑过马,特别有意思。
xiǎoshíhou wǒ qí guò mǎ, tèbié yǒu yìsi.
When I was little, I rode a horse, and it was really fun.
草原上有一群野马在奔跑。
cǎoyuán shàng yǒu yī qún yě mǎ zài bēnpǎo.
There is a herd of wild horses running on the grassland.