49. Which of the following books explores the origin of humans? 【】 (A)Seeking the Edge (B)Creation or Evolution. (C)Joshua, Helmut, and Bethlehem. (D)More Things in Heaven.

54. What can we learn about “the middle class” from Paragraph 2? 【】 (A)People earning ＄50,000 a year belong to the middle class. (B)Nearly half Americans belong to the middle class. (C)People generally consider bus drivers as the middle class. (D)Sociologists have a clear definition of the middle class.