diff --git a/02.01 基于搜索的问题求解(学生版).ipynb b/02.01 基于搜索的问题求解(学生版).ipynb
index 3abee10..9a54c71 100644
--- a/02.01 基于搜索的问题求解(学生版).ipynb
+++ b/02.01 基于搜索的问题求解(学生版).ipynb
@@ -48,10 +48,7 @@
     "from IPython import display\n",
     "import networkx as nx\n",
     "import numpy as np\n",
-    "import time\n",
-    "!cp ~/work/SimHei.ttf /home/jovyan/.virtualenvs/basenv/lib/python3.5/site-packages/matplotlib/mpl-data/fonts/ttf\n",
-    "plt.rcParams['font.sans-serif']=['SimHei']\n",
-    "plt.rcParams['axes.unicode_minus']=False"
+    "import time"
    ]
   },
   {
diff --git a/02.01 基于搜索的问题求解.ipynb b/02.01 基于搜索的问题求解.ipynb
index b367e3b..ecf975a 100644
--- a/02.01 基于搜索的问题求解.ipynb
+++ b/02.01 基于搜索的问题求解.ipynb
@@ -48,10 +48,7 @@
     "from IPython import display\n",
     "import networkx as nx\n",
     "import numpy as np\n",
-    "import time\n",
-    "!cp ~/work/SimHei.ttf /home/jovyan/.virtualenvs/basenv/lib/python3.5/site-packages/matplotlib/mpl-data/fonts/ttf\n",
-    "plt.rcParams['font.sans-serif']=['SimHei']\n",
-    "plt.rcParams['axes.unicode_minus']=False"
+    "import time"
    ]
   },
   {
diff --git a/02.02 决策树(学生版).ipynb b/02.02 决策树(学生版).ipynb
index eff7243..12fa846 100644
--- a/02.02 决策树(学生版).ipynb
+++ b/02.02 决策树(学生版).ipynb
@@ -536,15 +536,6 @@
    "metadata": {},
    "source": [
     "我们可以使用 graphviz 包来展示构建好的决策树。"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "pip install graphviz"
    ]
   },
   {
diff --git a/02.02 决策树.ipynb b/02.02 决策树.ipynb
index 1492b6a..f1f18d9 100644
--- a/02.02 决策树.ipynb
+++ b/02.02 决策树.ipynb
@@ -601,15 +601,6 @@
    "metadata": {},
    "source": [
     "我们可以使用 graphviz 包来展示构建好的决策树。"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "pip install graphviz"
    ]
   },
   {