Hi,
The answer lies in string.Format.
In resx file, use "About your {0} Tax Return" for the string value.
Then, in code, use string.format to place the year in the string:
lblAboutTaxReturn.text = String.Format(CultureInfo.InvariantCulture, Resources.myresources.AboutTaxReturnLabel, taxReturnYear);
lblAboutTaxReturn is the label that will be populated with the "About your ... Tax Return" text.
Resources.myresources.AboutTaxReturnLabel is a reference to the resx and the string you want to use.
taxReturnYear is the variable holding the year value for the tax return.
You can read more about string formatting here.
HTH,
Joe D.