一般过去时的特殊用法
a)在虚拟语气中表示现在或将来时间的动作或状态。
  It's time we went.
  该是我们走的时候了。
  I wish I were twenty years younger.
  但愿我年轻20岁。
  I would rather you didn't do anything for the time being.
  我宁愿你暂时先不要采取什么措施。
b)在口语中,一般过去时往往显示委婉客气。
  I wondered if you could give me a hand.
  我想请你帮个忙。
  Might I come and see you tonight?
  我想今晚来看你,好吗?