be to do sth约定,注定,必定“要做什么.指的人是对未来的一种计划，安排。
如:They were to meet at the usual place.
他们约好在老地方见．
be about to do sth正要做什么，如：
He was about to leave when the phone rang.
他正要离开就在这时电话响了．

If it were me（虚拟语气的用法）
1、表示与现在事实相反的情况： 　　
从句：If 主语+过去时 　　
主句：主语+should/would/could/might+do 　　
eg：If I were you,I would take an umbrella. 　　
如果我是你，我会带把伞。（事实：我不可能是你） 　　
If I knew his telephone number,I would tell you. 　　
如果我知道他的电话号码，我就会告诉你。（事实：不知道） 　　
If there were no air or water,there would be no living things on the earth. 　　
如果没有水和空气，地球上就不会有生物。(事实：地球上既有空气也有水) 　

2、表示与过去事实相反的情况 　　
从句：If 主语+had+done 　　
主句：主语+should/would/could/might+have done　　　
eg：If I had got there earlier,I should/could have met her.
如果我早到那儿，我就会见到她（事实：去晚了） 　　
If he had taken my advice,he would not have made such a mistake. 如果他听我的劝告的话，就不会犯这样的错误了（事实：没有听我的话） 　　

3、表示对将来情况的主观推测 　　
从句：①if+主语+were to do 主句：①主语+should/would/could/might+do 　　 ②if+主语+did/were ②主语+should/would/could/might+do　 　
　 ③if+主语+should+do ③主语+should/would/could/might+do　 　　
eg：If he should come here tomorrow,I would talk to him. 　　
如果他明天来这儿的话，我就跟他谈谈。（事实：来的可能性很小） 　　
If there were a heavy snow next Sunday,we would not go skating. 　 如果下周日下大雪，我们就不能去滑冰了。（事实：下雪可能性很小）

　　
4、 有时，虚拟条件句中，结果主句和条件从句的谓语动作若不是同时发生时，虚拟语气的形式应作相应的调整。这种条件句叫错综条件句。 　　
①从句的动作与过去事实相反，而主句的动作与现在或现在正在发生的事实不符。　　
eg：If I had worked hard at school,I would be an engineer,too. 　　
如果我在学校学习刻苦的话，我现在也会成为一个工程师了 　　
②从句的动作与现在事实相反，而主句的动作与过去事实不符。　　
如：If he were free today,we would have sent him to Beijing. 　　
如果他今天有空的话，我们会已经派他去北京了。
　　
5、 当虚拟条件句的谓语动词含有were,should,had时，if可以省略，这时条件从句要用倒装语序，即把were,should,had等词置于句首，这种多用于书面语。eg：Should he agree to go there,we would send him there. 　　
要是他答应去的话，我们就派他去。
　　
6、 有时，虚拟条件句中，主、从句可以省略其中的一个，来表示说话人的一种强烈的感情。 　　
①省略从句 He would have finished it. 他本该完成了。 　　
②省略主句 If I were at home now. 要是我现在在家里该多好啊。
7.注意，在虚拟语气的从句中，动词be的过去时态一律用were，不用was。　　 eg：If I were you,I would go to look for him. 如果我是你，就会去找他。