This question relates to a comment in another posting here: Cancelling an Entity Framework Query
I will reproduce the code example from there for clarity:
That comment doesn't make any sense as a using statement will be translated to a try/finally block by the compiler. Since 'entities' will not be used outside of the scope, it's easier to use a using statment as this will automatically dispose of the resources.
You can read more about this on MSDN: using Statement (C# Reference).