Since I won the big prize, my telephone _______ ringing. People are phoning to ask how I am going to spend the money.                              

A．didn’t stop

B．won’t stop

C．hasn’t stopped

D．doesn’t stop

匹配因素所占的比例，在病例组和对照组中是一致的，这种匹配是（）

A.个体匹配

B.群体匹配

C.频数匹配

D.标准匹配

E.匹配过度