Cars do cause us some health problems--in fact far more serious( )than mobile phones do. 25. Cars do cause people some ...

Cars do cause us some health problems in fact far more serious( )than mobile phones do.

\u6211\u8981\u662f\u56de\u7b54\u662f\u82f1\u6587\u7684\u4e60\u60ef\u7528\u6cd5\u697c\u4e3b\u662f\u4e0d\u662f\u4f1a\u6740\u4e86\u6211\uff1f\u5176\u5b9ethose\u5728\u8bed\u6cd5\u4e0a\u4e5f\u662f\u5bf9\u7684\uff0c\u4f46\u662f\u771f\u7684\u662f\u56e0\u4e3a\u897f\u65b9\u4eba\u90fd\u5728\u7528ones\u554a~\u6211\u66fe\u7ecf\u95ee\u8fc7\u4e00\u4e2a\u897f\u4eba\uff0c\u7ed9\u6211\u7684\u7b54\u6848\u5c31\u662f\u56e0\u4e3a\u662f\u4e60\u60ef\u7528\u6cd5

B. ones
\u4ee3\u8868\u524d\u9762\u5f97problems\uff0c= far more serious __problems___\u3002
those\u65e0\u6b64\u7528\u6cd5\u3002

serious是形容词，不能修饰those，these等代词。ones可以用serious修饰。