Hi,
I have two what seem to be similar sentences below and wish you could tell me why it is so.
I really have trouble distinguishing these two words yesterday. -- I think the word 'trouble' isn't specifying any instances or types of trouble here, so the word can be used although 'a trouble' can be used if a person have a concept of a type or an instance in place.
I had a discussion (note: cannot be 'discussion') about how to get a lot of work done in a shortest time possible with my collegues yesterday morning. -- Here, a person seems to have a specified picture of countable instance in his mind and the use of 'a discussion', rather than an uncountable 'discussion' is used.
Sorry, I hope this isn't a question on uncountables but rather a conceptual question.