常见连接词：if/in case/unless/as long as/so long as/suppose
You can stay to dinner if you like.
I wouldn’t have believed it if I hadn’t seen it happen.(虚拟语气）
If you work with me,I will take us to the top.
You‘d have more chance of catch the train if you took a bus to the station instead of working.
If I were you,I would not accept his apology.
If I had enough money,I might stop working and just go travelling.
If I had known you last year,I would have asked you to be my business partner.
If she hadn’t eaten too much candy,she might not have had her teeth pulled out.
Carry a gun in case there’s an ambush.|带上枪以防万一有埋伏。
Unless you are trying to lose weight to please yourself,it’s going to be tough to keep your motivation level high.
as long as/so long as:只要
I don’t care what is written in your history as long as/so long as you are here with me.
Suppose you had a million pounds,how would you spend it?
If you go to the party,you‘ll have a great time.
You may use the room as you like so long as you clean it up afterwards.
—What should we pay more attention to if we go north in winter,Mum?
—Nothing much.Take warm clothes in case the weather is cold.
It is a pity she isn’t here.If she were here,I would be happier.
If he had come with me yesterday,he would have gone to the beach.
as long as/so long as