a, Flatiron. 1- b, Sears tower, 2- c, Taipei 101. 3- d, World Trade Center. 4- e, Burj Dubai. 5- f, Equitable life building. 6- g, United Nation HQ. 7-
Ex 3 watch the video and complete the table
(complete columns E, F, G with concrete, stairs, steel, air-conditioning, sand, crane, elevator, windows )