like this, right?

using System;

namespace JS.Test
{
	public class Virtual
	{
		public static void Main()
		{

		}

		public abstract class A
		{
			public void Method()
			{
				OtherMethod();
			}

			public abstract void OtherMethod();
		}

		public class B : A
		{
			public override void OtherMethod()
			{
				Console.WriteLine("Concrete implementation");
			}
		}
	}
}