用括号说给的动词的适当形式补全对话

题目

用括号说给的动词的适当形式补全对话
hello! what's happened ?Didn't you catch your train?
If I__________(catch) it I ________(not ,be) here, should I ?

答案

had caught,wouldn't have been.
虚拟语气,表示与过去事实相反的情况
　　从句：主语+had+done
　　主句：主语+should/would/could/might+have done　
　　例如：
　　1． If I had got there earlier,I should/could have met her.如果我早到那儿,我就会见到她.（事实：去晚了）
　　2．If he had taken my advice,he would not have made such a mistake.如果他听我的劝告的话,就不会犯这样的错误了.（事实：没有听我的话）