Task 1

16. Paragraph     ①     

17. Paragraph     ②     

18. Paragraph     ③     

19. Paragraph     ④     

20. Paragraph     ⑤     

A. Lightening Causes Puzzles to People

B. Types of Lightning

C. Causes of Lightning

D. Differences Between Thunder and Thunderstorm

E. Frequencies of Thunderstorms Occurring in the World and the U. S.

F. Shock Waves as Thunder

Men like George Strong are important to the future of the company.

• A、True
  
  

• B、False
  
  

• C、Not Given
  
  

Compared with dreamless sleep, deep dream sleep is

• A、not the result of natural selection
  
  

• B、less likely to appear to monkeys
  
  

• C、more protective to the animals
  
  

• D、at a higher stage of evolution