Sources : JenniferESL
1. Water under the bridge – upleasant experience or event in the past. So it’s no longer considered important in the present.
Example : When the two sisters were teenagers, thy fought over boyfriends. That’s water under the bridge. Now they are both happily married, and they consider each other best friends.
2. Burn bridges – to leave a situation in such a way that you can never go back.
or to leave a relationship with one person or a group of people in such a way that you’ll never be welcome again.
Example : If you plan to quit your job, don’t burn bridges. Be professional and respectful when you make your announcement. Who knows? One day you need to ask for your old job back.
3. Cross that bridge when you come to it – to deal with a problem when it happens. You can’t cross a bridge until you’re acutally there. So why worry about possible problems?
Example : Don’t worry about paying tuition right now. You can cross that bridge when you come to it. Just focus on getting into a good university.
Sources : JenniferESL
Wonderful insight