using System;

public class Test
{
	public static void Main()
	{
		string titleID = "document for the period ended December 31 2014";
		string s1 = "ended ";
        string s2 = "Ended ";
        string s3 = "Ending ";
        string[] sArray = new[] { s1, s2, s3 };

        var stringMatch = System.Linq.Enumerable.FirstOrDefault(sArray, s =>  titleID.Contains(s));
        Console.Write(stringMatch);
	}
}