1．We ________ (enjoy) the sunshine in Sanya now if it were not for the delay of our flight．
答案：would be enjoying 句意：要不是耽搁了航班，我们现在正在三亚享受阳光。根据后面的“now”和“if it were not for ．．．”可知，此处是对现在状况的虚拟，故主句用would be doing。
2．When I was small, my mom ________ read me stories at night．
答案：would 句意：当我小时候，我母亲常常在晚上给我读故事。would “过去常常”，表示过去的习惯性的行为。
3．The accident ________ have been caused by a dog running across the road, but we don't know for sure．
答案：might 句意：事故可能是由一条横穿马路的狗引起的，但我们不确定。分析句子可知，本句是对过去动作的推测，可能性不大，故填might。
4．He looked so hungry as though he ________ (eat) a decent meal for a month．
答案：hadn't eaten 句意：他看起来如此饿好像已有一个月没有吃过一顿像样的饭了。由主句中的looked可知，as if/though后面跟过去完成时表示对过去的虚拟。
5．I was caught in a traffic jam for over an hour, otherwise, I ________ (keep) you waiting for such a long time．
答案：wouldn't have kept 句意：我在交通堵塞中被困了一个多小时，否则我不会让你等这么长时间。句中用了虚拟语气，otherwise说明的从句内容和过去事实相反，指如果不被交通阻塞困住，主句谓语动词用“would/should/could/might ＋have＋过去分词”形式。
