73. [A] when
　　[B] which
　　[C] why
　　[D] what
　　74. [A] prevalent
　　[B] poor
　　[C] primary
　　[D] productive
　　75. [A] to
　　[B] at
　　[C] in
　　[D] on
　　76. [A] such
　　[B] as
　　[C] so
　　[D] thus
　　77. [A] eyesight
　　[B] heart
　　[C] direction
　　[D] interest
　　78. [A] promised 考試網(wǎng)
　　[B] encouraged
　　[CJexposed
　　[D] propelled
　　79. [A] biochemically
　　[B] physically
　　[C] spiritually
　　[D] materially
　　80. [A} between
　　[B] among
　　[C] alike
　　[D] into