The "new set of wheels" that bicycle riders had to get used to was ______.
A. the new tires on their bikes
B. the automobile
C. the streetcar
D. the bicycle itself
A.contacting
B.connecting
C.uniting
D.combining
It was remarkable of man to invent the wheel because ______ .
A.it led to many other inventions
B.man had no use for it then
C.there were no wheels in nature
D.all of the above