15.The students were assigned to write a paper on ________ from the course.

  A.what had they learned                         B.that had they learned

  C.that they had learned                           D.what they had learned

16.A short sentence after a series of( 一系列 ) long sentences can have a dramatic ________.

  A.influence                                          B.result

  C.impression                                         D.effect

17.When he looked into the audience,he caught ________ of his mother nodding to him.

  A.sign                                                  B.sight

  C.glow                                                 D.head

18.Only then did he ________ the situation he and his fellow soldiers were in.

  A.aware                                               B.aware of

  C.become aware                                   D.become aware of

19.The hunter fired and the fox fell ________.

  A.death                                                B.deadly