We know for sure that colonization began at the end of the 15^th century.(  )

• A、Right

• B、Wrong

• C、Not mentioned

16. Paragraph?17. Paragraph?

18. Paragraph?

19. Paragraph?

20. Paragraph?

A. Main Results of Recent Researches

B. Difference between Genetic and Observed Intelligence

C. Effect of Environment on Intelligence

D. Intelligence and Achievement

E. Impact on School Education

F. A Changed View of Intelligence

The improvements the airlines attempt at include all the following EXCEPT   (  )

• A、making their seats more comfortable
• B、 providing better food during flights
• C、showing more movies during the long flights
• D、offering sleeperettes to first-class passengers