_湖南成考网

The main idea of this passage is____.

• A、warfare is a“law of nature”
  

• B、warfare is not a“law of nature”
  

• C、warfare does not control human population
  

• D、none of the lowlier animals, except ants，practice warfare upon their own species

28.请选择出最佳答案填入（　　）。

• A、broke away
  

• B、went out
  

• C、broke up
  

• D、turned out

55__________。