If you want to leave your computer for a while, you can directly close your laptop. However, the process that was originally running will be suspended or terminated. if the process is being downloaded, the download will be paused (sometimes cannot be recovered). If the network service is being provided, if the network is disconnected, no one else can connect to your notebook. Screen lock can solve this problem. In Windows, you can use the Win + L shortcut to lock the screen, but there is no default shortcut for Mac OS X. For new users like me, do not set the screen lock shortcut. Even if you want to use other screen lock methods, you can only find them online. One of the methods is to first find the "key string Access question" utility in the Finder (the specific location is/Applications/Utilities/Keychain Access. app), and then select "display key string status in the menu bar" in "preference settings ". At this time, we found that the system menu has a small icon like a lock, and you only need to click it to find the lock screen. The above method achieves the lock screen, but it still fails to achieve the goal of controlling the lock screen with shortcuts. Even so, its effect gives us a screen lock idea. First, we require the screen saver to enter a password upon recovery, and then the screen lock problem becomes the problem of starting the screen saver. Step 1: Find "Security and Privacy" under "system preference settings" and check "enter the password immediately after Entering sleep or Starting Screen Saver" on the "General" page ". Step 2: Use the shortcut key to start the screen saver, which is more complex. Find "Automator" in "application ". Create a new service, find "Start Screen Saver" in "utility" under "operation", and drag this operation to the right, select "no input" and "any application", as shown in. Save the service as your own name. Finally, find "keyboard" in "system preference settings" and configure the shortcut key for the service just defined. I set it to Command + Control + L.