Correct README spelling mistakes

README.md

@@ -107,7 +107,7 @@ Mars.onCreate(true);
 BaseEvent.onForeground(true);
 StnLogic.makesureLongLinkConnected();
 ```
-Firstly, you should call the setCalBack interface, and secondly, the Mars.init. Then, to initialize the Mars, there is to need to strictly follow the orders of the four commands. Finally, after Mars are initialized, onForeground and makesureLongLinkConnect can be called.
+Firstly, you should call the setCallBack interface, and secondly, the Mars.init. Then, to initialize the Mars, there is to need to strictly follow the orders of the four commands. Finally, after Mars are initialized, onForeground and makesureLongLinkConnect can be called.
 
 Destroy STN or exit your app: