diff --git a/01.01 python 基础.ipynb b/01.01 python 基础.ipynb
index 8d9ddcb..1e1a307 100644
--- a/01.01 python 基础.ipynb
+++ b/01.01 python 基础.ipynb
@@ -801,12 +801,23 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 1,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "1"
+      ]
+     },
+     "execution_count": 1,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "a = [10, 11, 12, 13, 11]\n",
-    "a.index(12)"
+    "a.index(11)"
    ]
   },
   {
@@ -818,9 +829,20 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 2,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "2"
+      ]
+     },
+     "execution_count": 2,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "a = [10, 11, 12, 13, 11]\n",
     "a.count(11)"
diff --git a/01.02 python 进阶.ipynb b/01.02 python 进阶.ipynb
index f96902d..69c6dbd 100644
--- a/01.02 python 进阶.ipynb
+++ b/01.02 python 进阶.ipynb
@@ -1345,6 +1345,52 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
+    "### else\n",
+    "\n",
+    "`try/except` 块有一个可选的关键词 `else`。\n",
+    "\n",
+    "如果使用这个子句，那么必须放在所有的 except 子句之后。else 子句将在 try 子句没有发生任何异常的时候执行。"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "try:\n",
+    "    print (1)\n",
+    "except:\n",
+    "    pass\n",
+    "else:\n",
+    "    print ('else was called.')"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "出现异常，else 不会执行。"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "try:\n",
+    "    print (1/0)\n",
+    "except ZeroDivisionError:\n",
+    "    print ('divide by 0.')\n",
+    "else:\n",
+    "    print ('else was called.')"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
     "### finally\n",
     "\n",
     "`try/except` 块还有一个可选的关键词 `finally`。\n",
diff --git a/01.03 机器学习常用的包.ipynb b/01.03 机器学习常用的包.ipynb
index 67764d2..1ec596a 100644
--- a/01.03 机器学习常用的包.ipynb
+++ b/01.03 机器学习常用的包.ipynb
@@ -452,7 +452,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "# 数组的形状被修改为: (4, 20), -1: 表示通过待计算\n",
+    "# 数组的形状被修改为: (2, 12), -1: 表示通过待计算\n",
     "c = a.reshape([-1,12])\n",
     "c\n"
    ]