diff --git a/.gitmodules b/.gitmodules
index b83a5859a86cb172259c6454b331fdd828eaf24c..f472ee8b12301692eb9ebcbf1aaa3beff1d9ff17 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,6 +1,3 @@
-[submodule "book/external/learn-programming"]
-	path = book/external/learn-programming
-	url = git@github.com:TeachBooks/learn-programming.git
 [submodule "book/external/learn-python"]
 	path = book/external/learn-python
 	url = https://github.com/TeachBooks/learn-python.git
diff --git a/book/external/learn-programming b/book/external/learn-programming
deleted file mode 160000
index 9ee111909509ec516695737fd0a0a1ef32c8a9d6..0000000000000000000000000000000000000000
--- a/book/external/learn-programming
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 9ee111909509ec516695737fd0a0a1ef32c8a9d6
diff --git a/book/modelling/Jialei Test b/book/modelling/Jialei Test
new file mode 100644
index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391