So when do we use virtual methods and when do we use abstract classes?

Answer 1

An abstract class can be inherited but not instanced☺
thats like when you work with others and dont want them to do it by mistake, or if you want to ensure you wont forget it 😜

A virtual method is used when you probably want to redefine a method in a subclass. Then to do it you just use the "override" word.
😊
For example:

using System;
namespace VirtualTesting
{
class Program
{
static void Main(string[] args)
{
Animal someanimal = new Animal();
Animal neko=new Gato();
someanimal.talk();
neko.talk();
Console.ReadKey();
}
}
class Animal
{
public virtual void talk()
{
Console.Write("I'm an animal");
}
}
class Gato : Animal
{
public override void talk()
{
Console.Write("Im a cat");
}
}

}
results:
I'm an animal
I'm a cat

You will get different results by doing these:
1. using "abstract" before "class Animal" -> wont work😂. unless you erase the "someanimal" variable 😉
2. removing "virtual" and "override" words -> will show only the generic animal words

Hope you understand, because I'm not so good in English 😜