Question

I need two ________.

1. A.
   rolls of film
2. B.
   rolls of films
3. C.
   roll of film
4. D.
   roll of films

Answer 1

A
此题意思为“我需要两卷胶卷”。film是不可数名词，不能加s，一卷胶卷可说成a roll of film，二卷胶卷应为two rolls of film，与之用法相同的短语还有：three pieces of bread，four bottles of water，five boxes of chalk等。