(2013·陕西师大附中模拟)If we had taken such effective measures much earlier, the river so seriously now.
A. is not polluted
B. would not be polluted
C. had not been polluted
D. would not have been polluted
网友回答
A. is not polluted
(答案→)B. would not be polluted
C. had not been polluted
D. would not have been polluted
解析：选B 句意：如果我们早采取有力措施，现在河水就不会污染这么严重。主句表示与现在事实相反的虚拟语气，用would加动词原形。