Period Two Learning about Language虚拟语气(二)1．与过去事实相反的虚拟条件句在该类条件句中，条件从句中的谓语动词用 had＋过去分词，主句中的谓语动词用would/should/might/could＋have＋过去分词
If he had known the facts, he could have told us what to do
如果他了解事实，他就能告诉我们怎样做
If I had been less cautious, I might have been more wise
如果我不那么谨慎，我或许更明智
If he had received the present，he should have thanked her
如果他收到了礼物，他是应当向她道谢的
2．对将来情况假设的虚拟条件句该类条件句表示将来实现的可能性不大
if 从句中的谓语动词可以用三种形式，即should ＋ v
, were to ＋ v
或 动 词 的 过 去 式 ， 主 句 中 的 谓 语 动 词用 should/would/could/might＋v
If you dropped the glass, it would break
杯子摔下来会打碎的
If I were to go to the moon some day, I could see the surface of the moon with my own eyes
＝ If I should go to the moon some day
＝ If I went to the moon some day
要是有一天我上了月球，我就能亲眼看到月球的表面是什么样子了
If it were to rain tomorrow, the meeting would be
