单选题Though many of the h

问题补充：

单选题Thoughmanyoftheheavysmokershaverealizedtheseriouseffectthatsmokinghas______theirhealth,theycontinuetosmokeinsteadof______.A.for; giving it upB.on; quittingC.to; abandoningD.on; leaving

答案：

B解析考查固定搭配。the serious effect是先行词，that smoking has ______ their health是定语从句，把先行词代入定从，是 smoking has the serious effect____ health，构成have an effect on 结构，所以第一空用on;根据句意：他们继续吸烟而不是戒掉。Quit停止，终止。所以选B。