According to the passage, in operating airlines it is essential to     .(  )

• A、keep in mind the need. of the executives only
• B、satisfy the need of the low fare passengers at the expense of the executives
• C、try to attract as many passengers as possible by reducing fares
• D、cater to the need of passengers setting at both ends of the jets

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

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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