<prompt> Translate the following text to EnglishHii ni dhana ya kihafidhina sana kwa sababu mitambo ya FGD ngumu zaidi itahitaji miaka mitatu wakati wakati halisi unaopatikana kukamilisha upgrades zilizopangwa kwa kila kipindi, isipokuwa kabla ya 2005, ni miaka mitano.  <response>: This is a very conservative assumption because the most complex FGD installations will require three years while the actual available time to complete the projected retrofits for each period, except prior to 2005, is five years. 