The information provided in the passage is for people who travel by （）
A. plane
B. train
C. ship
D. bus
According to the passage, subways are underground trains, which usually run （）
A. within downtown areas
B. away from city centers
C. in or outside big modem cities
D. between suburbs and city centers
Plateau"s experiments were the first step leading to the invention of（）
A. eyeglasses
B. telescopes
C. bifocals
D. motion pictures
I think these traditional customs should be ______.
A. stayed
B. remained
C. reserved
D. preserved
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