According to the American federal government, residents of Hawaii have the longest life ______ 77.2 years.

单项选择题In order to recover their share of the world market, U.S. auto makers are （）

A．improving product quality
B．modernizing product style
C．repositioning their product in the market
D．increasing product features

单项选择题The author mentions the example of backpacks ( Line 4, Para. 2 ) to show the importance of（）

A．increasing usage among students
B．exploring new market sections
C．pleasing the young as well as the old
D．serving both military and civil needs