Update 2.meta-service.md (#622)

docs-2.0/1.introduction/3.nebula-graph-architecture/2.meta-service.md

@@ -1,14 +1,14 @@
 # Meta Service
 
-This article will introduce the architecture and functions of the Meta Service.
+This topic introduces the architecture and functions of the Meta Service.
 
 ## The architecture of the Meta Service
 
 The architecture of the Meta Service is as follows:
 
 ![The architecture of the Meta Service](https://docs-cdn.nebula-graph.com.cn/docs-2.0/1.introduction/2.nebula-graph-architecture/meta-architecture1.png)
 
-The Meta Service is run by the nebula-metad processes. Users can deploy nebula-metad processes according to the scenario:
+The Meta Service is run by nebula-metad processes. Users can deploy nebula-metad processes according to the scenario:
 
 * In a test environment, users can deploy one or three nebula-metad processes on different machines or a single machine.
 * In a production environment, we recommend that users deploy three nebula-metad processes on different machines for high availability.