辨认主题句

Read the following paragraph, find out the topic sentence and write it on the answer sheet. 

         The tragic hero is typically on top of the wheel of fortune, half-way between human society on the ground and something greater in the sky. Prometheus, Adam, and Christ hang between heaven and earth, between a world of paradisal (天堂似的) freedom and a world of bondage. Tragic heroes are so much the highest points in their human landscape that they seem the inevitable conductors of the power about them, great trees more likely to be struck by lightning than a clump of grass. Conductors may of course be instruments as well as victims of the divine lightning: Milton’s Samson destroys the Philistine temple with himself, and Hamlet nearly exterminates (消灭)the Danish court in his own fall.