Updates 家长端服务/接口文档.md

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@@ -140,7 +140,11 @@ GET  https://api.boxfish.cn/parents/learning/{student_id}/{date}?access_token=pa
  "date": "2016-11-29"
  }
 ```
+### 家长查询学生周学习时长接口
+```
+GET https://api.boxfish.cn/parents/learning-between/100000000721/2016-11-25/2016-11-27?access_token=parent0
 
+```
 
 ### 数据库设计