diff --git a/20.test/35.temporaryDsystem/20.b/textbook.en.md b/20.test/35.temporaryDsystem/20.b/textbook.en.md
index 79b2a8dd3..d45c88519 100644
--- a/20.test/35.temporaryDsystem/20.b/textbook.en.md
+++ b/20.test/35.temporaryDsystem/20.b/textbook.en.md
@@ -1,10 +1,10 @@
 ---
 lessons:
-    - slug: test01-en
+    - slug: test01-Len
       order: 2
-    - slug: test02-en
+    - slug: test02-Len
       order: 1
-    - slug: test03-en
+    - slug: test03-Len
       order: 3
 ---