diff --git a/src/core/manager/StateManager.ts b/src/core/manager/StateManager.ts
index 43b3c6c..ba68391 100644
--- a/src/core/manager/StateManager.ts
+++ b/src/core/manager/StateManager.ts
@@ -49,6 +49,13 @@ interface HistoryStep {
  * stateManager.undo()
  * stateManager.redo()
  *
+ * // 用例4 多连线
+ * stateManager.beginStateUpdate();stateManager.vdata.items[0].dt.center.push('p3');stateManager.vdata.items[2].dt.center.push('p1');stateManager.endStateUpdate();
+ * stateManager.undo()
+ *
+ * // 用例5 删除线
+ * stateManager.beginStateUpdate();stateManager.vdata.items[0].dt.center=[];stateManager.vdata.items[1].dt.center.splice(0,1);stateManager.endStateUpdate();
+ * stateManager.undo()
  */
 export default class StateManager {
   /**