This worked for me:
string htmlText = @"{0}<tr style="" border-removed="" 0=""><td style="" border-removed="" 75px="">{1}</td><td style="" border-removed="" 0="">{2}</td></tr>";
string[] plainTexts = new string[3];
plainTexts[0] = " ";
plainTexts[1] = "foo";
plainTexts[2] = "bar";
string result = string.Format(htmlText, plainTexts);