求一下下面这几题怎么写

...写了好久忽然看见是两年前的问题, 但是还是麻烦你采纳把

            //题目1
            Console.WriteLine("Hello, " + "Console.ReadLine()");

            //题目2
            int a = 1;
            int b = 2;
            Console.WriteLine(a + b);

            //题目3
            string inputContent = Console.ReadLine();
            string[] array = inputContent.Split('/');

            int Y = Convert.ToInt32(array[0]);
            int M = Convert.ToInt32(array[1]);
            int D = Convert.ToInt32(array[2]);

            int index = D;
            int[] months = { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
            
            //闰年
            if (!(Y % 4 == 0 && Y % 100 != 0 || Y % 400 == 0))
                months[1] = 28;

            for (int i = 1; i < M; i++)
            {
                index += months[i];
            }

            Console.WriteLine("该日是今年的第" + index + "天");//在这里被调用