The screen of my macbook suddenly broken down how can I do to recover

Depending on the age of your MacBook, you'll have one or more connections on the side that an external screen can connect to. When you identify your MacBook you'll be able figure out the best way to connect a screen, whether it's directly or using an adaptor.

If the external monitor doesn't help, the onboard graphics may have gone pop, which might have affected the screen. In that case, go the Target Disk mode route -- but you'll need another Mac and a connecting lead (Thunderbolt or Firewire depending the age of the MacBook) for it to work.

The easy way to access files and back them up is to connect to another Mac via target disk mode. Just the bare minimum parts of the system like the disk controller and selected bus need to work.

• Does working in Target Disk mode hurt hardware?

Apple has support articles and dozens of questions here cover most of the common scenarios to use target disk mode. If you need to pay someone to transfer the files - start with your school IT team and once you're set, ask them for guidance to store critical files in the cloud or set up a backup. For now you'll need to determine if the files are accessible and then plan your next steps.