C#中switch语句可以嵌套使用吗

int number = 2;
int letter = 1;

switch (number)
{
    case 1:
        Console.WriteLine("Number is 1");
        switch (letter)
        {
            case 1:
                Console.WriteLine("Letter is A");
                break;
            case 2:
                Console.WriteLine("Letter is B");
                break;
            default:
                Console.WriteLine("Letter is unknown");
                break;
        }
        break;
    case 2:
        Console.WriteLine("Number is 2");
        break;
    default:
        Console.WriteLine("Number is unknown");
        break;
}