Potatoes are my favourite vegetables.vegetable是否要加s?

Potatoes are my favourite vegetables.vegetable是否要加s?
Potatoes are my favourite vegetables.vegetable是否要加s?

Potatoes are my favourite vegetables.vegetable是否要加s?
不用加s.

vegetable是不可数的，无复数，希望我能帮助你解疑释惑。