[填空题]
The Eiffel Tower (Fig. 13–29) is bu5h+-a xd:hd qiilt of wrought iron approximatelra4kr.csf y0/x( sbc6 y 300 m tall. Estimate how much its height changes betweyas0x (c.6sbf4k rr c/en July (average temperature of 25°C) and January (average temperature of 2 $^{\circ} $ C). Ignore the angles of the iron beams, and treat the tower as a vertical beam. m