Dictionaries (http://www.macmillandictionary.com/dictionary/british/difference http://www.ldoceonline.com/dictionary/difference) say "difference" can be used both as a countable noun and an uncountable noun. I am confused with it. I am wondering when I should use "difference" or "differences".
1 Answer
Think it in a normal way. When do you use 'car' and 'cars'? There is a car, if there's only one car and there are cars, when there are more than one. Clear?
Similarly, we use a singular form when we mean or expect one difference.
There is a difference in the quality of these two items. This one has a 'thicker' plastic.
So, the 'thickness of the plastic' used for that thing is the difference (only one difference) you find.
On the other hand, we use a plural form when we expect more than one difference.
Find the three differences in these two pictures
You asked when to use what? It's worth to note that when we talk about a disagreement, we generally use the plural form (Probably it's because we are not sure the number of differences!)
They had a terrible argument a few weeks ago, but now they've settled/resolved their differences.