using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        List<A>b = new List<A>();

        for(int i = 0;i<20;i++){

            b.Add(new A(i.ToString()+'c'));

        }

        var list = b.Select(x=>x.a);

        var list2 = b.SelectMany(x=>x.a);

        list.ToList().ForEach(Console.WriteLine);

        list2.ToList().ForEach(Console.WriteLine);

    }

}

​

class A{

    public string a;

    public A(string o){

        this.a=o;

    }

}