Question

By the time you get to Beijing tomorrow, I ________ for Shanghai.

A) am leaving
B) should have left
C) will leave
D) have already left 答案是b啊 b不是对过去的推测吗 那这句话的意思是
（现在的角度）在明天你到北京之前，我（过去）应该到上海了。 是不是我逻辑有大大的错误啊 求老师骂醒 谢谢！

Answer 1

By the time you get to Beijing tomorrow, I __should have left__ for Shanghai.
B) should have left
明天你到北京之的时候，我应该已经出发去上海了。
不是你逻辑有大大的错误。
这是个虚拟语气。表示对未来的判断。没道理讲，死记这个句套子不费劲弄懂道理更好！！
祝你学习进步！！！！

Answer 2

是一种对将来的推测，所以用的should have的虚拟语气

追问

should 有对未来的猜测吗 森三 老师么交过呀

追答

这是虚拟语气的一种用法，表示对一个尚未发生事件的推测，有可能发生也有可能不发生。如：
She should have got the letter this morning. I expect she'll give us a call about it later.

He should have arrived at his office by now. Let's try ringing him.
They should have all read that first email by this stage. It's time to send the next one.

追问

我网上找不到你说的未发生的推测，请看链接 森三 http://zhidao.baidu.com/link?url=C77n8n0VQd7Srxy2KL5Rk9vJYKDOzfx3SvnOYk-W7L7GUFnG-xH78ZQLL-DYiC_M1dnsjwyG2JSE2yDWdV_Sjq