!5341 【OpenHarmony开源贡献者计划2022】[英文]ability表达问题

Merge pull request !5341 from king_he/0613-a

en/application-dev/ability/stage-serviceextension.md

 # Service Extension Ability Development
 
 ## When to Use
-**ExtensionAbility** is the base class of the new **Extension** component in the stage model. It is used to process jobs without UIs. The lifecycle of an Extension ability is simple, and it does not involve foreground or background. **ServiceExtensionAbility** is extended from **ExtensionAbility**.
+**ExtensionAbility** is the base class of new **Extension** components in the stage model. It is used to process jobs without UIs. The lifecycle of **ExtensionAbility** is simple and does not involve foreground or background. **ServiceExtensionAbility** is extended from **ExtensionAbility**.
 
-You can customize a class that inherits from **ServiceExtensionAbility** and override the lifecycle callbacks of **ServiceExtensionAbility** to perform service logic operations during the initialization, connection, and disconnection processes.
+You can customize a class that inherits from **ServiceExtensionAbility** and override the lifecycle callbacks of **ExtensionAbility** to perform service logic operations during the initialization, connection, and disconnection processes.
 
 ## Available APIs