What can replace string interpolation in C# 5?

Question

.NET

Interpolation has been available since C# 6. Are there any other ways to concatenate strings in C#5 other than this way:

public void Print(string str)
    {
      Console.WriteLine(DateTime.Now + str +" Ok!");
    }

It's easy to get confused.

Answer 1

public void Print(string str)
{
      Console.WriteLine(string.Format("{0} {1} Ok!", DateTime.Now, str));
}

Answer 2

There is string.Format, there is StringBuilder.