DavidT

Hello all, I took an online test with the following question and had to fill in the correct Ser or Estar form. Esas ventanas ________ hechas de vidrio. I put in "son" but the correct answer is "esta'n" and I don't understand why. I went with "son" due to the window being glass as something permanent and possibly a characteristic...both "son" tendencies. Any help would be greatly appreciated, Thanks! David