Most people believe that ____knowledge is power and that having ____ good command of a

foreign language is of great importance .

A．/ , / ,

B．the , a ,

C．/ , a ,

D． /, the

一份有关吸烟与肺癌关系的病例对照研究结果显示：x2=12.36，p<0.05，OR=3.3，正确的结论是（）

A.对照组发生肺癌的可能性大于病例组

B.对照组肺癌的患病率明显大于病例组

C.病例组肺癌患病率明显大于对照组

D.病例组发生肺癌的可能性大于对照组

E.不吸烟者发生肺癌的可能性小于吸烟者