diff --git a/assist09_analysis.ipynb b/assist09_analysis.ipynb
index 8d007ee..b6cf20a 100644
--- a/assist09_analysis.ipynb
+++ b/assist09_analysis.ipynb
@@ -11,7 +11,8 @@
     "Skill builder 数据也称为掌握学习数据。该数据集来源于**技能训练**练习题组。当学生达到特定标准（通常设定为连续正确回答3道题）时，即被视为已掌握某项技能，此后系统将不再提供与该技能相关的题目。\n",
     "\n",
     "# 数据集列含义\n",
-    "- order_id：原始问题日志的ID\n",
+    "- order_id：问题日志的ID\n",
+    "  - 按照时间顺序排列\n",
     "- assignmet：课程ID\n",
     "- user_id：学生ID\n",
     "- assistment_id：辅助问题ID\n",