diff --git a/index.js b/index.js
index 59d6c84..eed69ac 100644
--- a/index.js
+++ b/index.js
@@ -1,41 +1,57 @@
 function myPromise(constructor) {
   let self = this;
 
-  self.status = "pending" //定义状态改变前的初始状态
+  self.status = "pending"; //定义状态改变前的初始状态
 
-  self.value = undefined;//定义状态为resolved的时候的状态
+  self.value = undefined; //定义状态为resolved的时候的状态
 
-  self.reason = undefined;//定义状态为rejected的时候的状态
+  self.reason = undefined; //定义状态为rejected的时候的状态
 
-  function resolve(value) {
+  self.fulfillTasks = [];
+
+  self.rejectTasks = [];
 
-    // TODO resolve如何改变状态及返回结果
+  function resolve(value) {
+    if (self.status !== "pending") return;
 
+    self.status = "fulfilled";
+    self.value = value;
+    self.fulfillTasks.forEach((fn) => fn());
   }
 
   function reject(reason) {
+    if (self.status !== "pending") return;
 
-    // TODO reject如何改变状态及返回结果
-
+    self.status = "rejected";
+    self.reason = reason;
+    self.rejectTasks.forEach((fn) => fn());
   }
 
   //捕获构造异常
 
   try {
-
     constructor(resolve, reject);
-
   } catch (e) {
-
     reject(e);
-
   }
-
 }
 
 myPromise.prototype.then = function (onFullfilled, onRejected) {
+  // skip creating new promise
+  if (this.status === "fulfilled") {
+    onFullfilled(this.value);
+  } else if (this.status === "rejected") {
+    onRejected(this.reason);
+  }
 
-  //TODO then如何实现
+  if (this.status === "pending") {
+    this.fulfillTasks.push(() => {
+      onFullfilled(this.value);
+    });
 
-}
-module.exports = myPromise
+    this.rejectTasks.push(() => {
+      onRejected(this.reason);
+    });
+  }
+};
+module.exports = myPromise;