SQL server :Use variable to hold string of size greater than 8000.

Question

Hello All,

           I am using SQL Server 2008. In my Sproc i am taking big sql query in nvarchar(max) type variable and execute it with exec....but the problem is that its exceeding limits and i am not able to execute whole query.my query size is 9778.
 
help me if you know the solution for this problem.