If she had not had an alarm clock,she would have missedthe t

绝对不可以的 表示与过去事实相反的虚拟条件句.其句子结构为：
从句：If + 主语+ had +过去完成式动词+ ……
主句：主语+ would (should, could, might) + have +过去完成式动词+……
例如:
⑴、If you had taken my advice, you would not have made such a mistake.如果你听了我的劝告,就不会犯这样的错误.（事实上你没有听我的劝告）