Which of the following is a bad habit of the executive passengers that frustrates the airlines?(  )

• A、They do not book their seats in advance.
• B、They do not sit on the seats they are supposed to take.
• C、They do not travel on the flight they have booked.
• D、They do not pay in advance for the seats they book.

A. goal

B. hug

C. entered

D. run

E. promise

F. true

G. proud

H. rest

I. get through

J. encouraging

K. testing

L. preparing

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