diff --git a/examples/cocos-creator-multiplayer/backend/src/shared/game/GameSystem.ts b/examples/cocos-creator-multiplayer/backend/src/shared/game/GameSystem.ts
index b90dd89..516a158 100644
--- a/examples/cocos-creator-multiplayer/backend/src/shared/game/GameSystem.ts
+++ b/examples/cocos-creator-multiplayer/backend/src/shared/game/GameSystem.ts
@@ -3,9 +3,13 @@ import { ArrowState } from "./state/ArrowState";
 import { PlayerState } from "./state/PlayerState";
 
 export interface GameSystemState {
+    // 当前的时间（游戏时间）
     now: number,
+    // 玩家
     players: PlayerState[],
+    // 飞行中的箭矢
     arrows: ArrowState[],
+    // 箭矢的 ID 生成
     nextArrowId: number
 }
 
@@ -119,4 +123,9 @@ export interface TimePast {
     type: 'TimePast',
     dt: number
 }
-export type GameSystemInput = PlayerMove | PlayerAttack | PlayerJoin | PlayerLeave | TimePast;
\ No newline at end of file
+
+export type GameSystemInput = PlayerMove
+    | PlayerAttack
+    | PlayerJoin
+    | PlayerLeave
+    | TimePast;
\ No newline at end of file
diff --git a/examples/cocos-creator-multiplayer/backend/src/shared/game/state/ArrowState.ts b/examples/cocos-creator-multiplayer/backend/src/shared/game/state/ArrowState.ts
index b2d9531..42493d8 100644
--- a/examples/cocos-creator-multiplayer/backend/src/shared/game/state/ArrowState.ts
+++ b/examples/cocos-creator-multiplayer/backend/src/shared/game/state/ArrowState.ts
@@ -1,6 +1,9 @@
 export type ArrowState = {
     id: number,
+    // 谁发出的箭
     fromPlayerId: number,
+    // 落地时间（游戏时间）
     targetTime: number,
+    // 落点位置（游戏位置）
     targetPos: { x: number, y: number }
 }
\ No newline at end of file