using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Dictionary<string, string> dict = new() {

            {"A", "apple"},

            {"B", "berry"},

            {"C", "citrus"},

            {"D", "durian"},

        };

        Console.WriteLine("Before:");

        foreach(var item in dict) {

            Console.WriteLine(item.Key + ": " + item.Value);

        }

        Console.WriteLine("Removing...");

        foreach(var item in dict) {

            dict.Remove(item.Key);

        }

        Console.WriteLine("After:");

        foreach(var item in dict) {

            Console.WriteLine(item.Key + ": " + item.Value);

        }

    }

}

​