pizza是不可数名词，那一份pizza怎么说啊？还有牛排是可数名词吗？两份牛排怎么说啊？

a piece of pizza
牛排是可数名词: two steaks

问题补充: 一般购买时不说a portion of pizza, 或two portions of beefsteaks. portion不能这样用.

How big is the portion of the pizza(steak)?问一片/块pizza(steak)到底有多大?
It's a big portion.这么多啊.

"large pizza" pizza有大中小之分,是指在没切以前的大小. pizza是不可数名词, 但日常生活中有很多事情是没有按照语法的:
two beers, 两杯啤酒, 这在酒吧非常常见.
two cokes = two cans of coke,
但英语考试时你只有一个正确的选择, 你不能说"我听美国这样说过"

a portion of pizza 一份比萨饼
a piece of pizza 一块比萨饼
牛排是可数名词.
two portions of beefsteaks 两份牛排
two steaks 两块牛排
portion n.(食物的)一份,一客

a piece of pizza

two beefsteak