issue
What does the phrase"money is an issue" mean?
It is like-it is important?or ssomething to take into account? Can I say prepositions are an issue to mean they are important to be learnt or tricky ?

Question

issue
What does the phrase"money is an issue" mean? 
It is like-it is important?or ssomething to take into account? Can I say prepositions are an issue to mean they are important to be learnt or tricky ?

Answer

In this case, "issue" can be understood as "problem", or "something I'm struggling with".
"Money is a problem" could be written as "I don't have enough money", and "prepositions are a problem" could be written as "I find prepositions difficult".

Hope that helps!