填空题 If Robinson ______ (learn) how to swim, he wouldn't have been trapped on that island.

  • 1、
【正确答案】 1、had learned    
【答案解析】[考点] 虚拟语气
[解析] 从主句would have been trapped可知题中描述的是与过去事实相反的的假设，因此if从句应用had done的形式。