Cars do cause us some health problems——in fact far more serious than mobile phones do.
A. one
B. ones
C. it
D. those
网友回答
A. one
(答案→)B. ones
C. it
D. those
解析:考查代词:句意:汽车会带给我们很多健康问题,--实际上比手机的问题还要多。这里需要代词指代problems,用ones指代可数名词的复数,one是泛指可数名词单数,it是特指同类同物。Those是特指可数名词复数,而且后面有后置定语。选B。