be to do sth約定,注定,必定“要做什么.指的人是對未來的一種計劃，安排。
如:They were to meet at the usual place.
他們約好在老地方見．
be about to do sth正要做什么，如：
He was about to leave when the phone rang.
他正要離開就在這時電話響了．

If it were me（虛擬語氣的用法）
1、表示與現在事實相反的情況： 　　
從句：If 主語+過去時 　　
主句：主語+should/would/could/might+do 　　
eg：If I were you,I would take an umbrella. 　　
如果我是你，我會帶把傘。（事實：我不可能是你） 　　
If I knew his telephone number,I would tell you. 　　
如果我知道他的電話號碼，我就會告訴你。（事實：不知道） 　　
If there were no air or water,there would be no living things on the earth. 　　
如果沒有水和空氣，地球上就不會有生物。(事實：地球上既有空氣也有水) 　

2、表示與過去事實相反的情況 　　
從句：If 主語+had+done 　　
主句：主語+should/would/could/might+have done　　　
eg：If I had got there earlier,I should/could have met her.
如果我早到那兒，我就會見到她（事實：去晚了） 　　
If he had taken my advice,he would not have made such a mistake. 如果他聽我的勸告的話，就不會犯這樣的錯誤了（事實：沒有聽我的話） 　　

3、表示對將來情況的主觀推測 　　
從句：①if+主語+were to do 主句：①主語+should/would/could/might+do 　　 ②if+主語+did/were ②主語+should/would/could/might+do　 　
　 ③if+主語+should+do ③主語+should/would/could/might+do　 　　
eg：If he should come here tomorrow,I would talk to him. 　　
如果他明天來這兒的話，我就跟他談談。（事實：來的可能性很小） 　　
If there were a heavy snow next Sunday,we would not go skating. 　 如果下周日下大雪，我們就不能去滑冰了。（事實：下雪可能性很小）

　　
4、 有時，虛擬條件句中，結果主句和條件從句的謂語動作若不是同時發生時，虛擬語氣的形式應作相應的調整。這種條件句叫錯綜條件句。 　　
①從句的動作與過去事實相反，而主句的動作與現在或現在正在發生的事實不符。　　
eg：If I had worked hard at school,I would be an engineer,too. 　　
如果我在學校學習刻苦的話，我現在也會成為一個工程師了 　　
②從句的動作與現在事實相反，而主句的動作與過去事實不符。　　
如：If he were free today,we would have sent him to Beijing. 　　
如果他今天有空的話，我們會已經派他去北京了。
　　
5、 當虛擬條件句的謂語動詞含有were,should,had時，if可以省略，這時條件從句要用倒裝語序，即把were,should,had等詞置于句首，這種多用于書面語。eg：Should he agree to go there,we would send him there. 　　
要是他答應去的話，我們就派他去。
　　
6、 有時，虛擬條件句中，主、從句可以省略其中的一個，來表示說話人的一種強烈的感情。 　　
①省略從句 He would have finished it. 他本該完成了。 　　
②省略主句 If I were at home now. 要是我現在在家里該多好啊。
7.注意，在虛擬語氣的從句中，動詞be的過去時態一律用were，不用was。　　 eg：If I were you,I would go to look for him. 如果我是你，就會去找他。