diff --git a/res/doc/sample_en.yaml b/res/doc/sample_en.yaml
index 94a9610f38e36881df532e4256b62ff94db4b3e5..8143f82d146e8a89cb0c67c3445c76971afa3c78 100644
--- a/res/doc/sample_en.yaml
+++ b/res/doc/sample_en.yaml
@@ -49,6 +49,7 @@ desc:
     # Elements can be a range, e.g. range:1-10, A-Z.
     # Use colons to define steps, e.g. range:1-10:2.
     # Steps can be decimals, e.g. range: 1-10:0.1.
+    # Steps can be negative, e.g. range: 9-1:-1
     # Intervals can be set as random by R, e.g. range: 1-10:R. Set either random or a specified step.
     # Use a file to specify a list, e.g. range: list.txt. If the file name is a relative path, it is based on the config file.
     # Use {n} to repeat a element, e.g. range: user1{100},user2{100}.
@@ -64,16 +65,16 @@ fields:
     prefix: int_                        # Prefix
     postfix: "\t"                       # Postfix
 
-  - field: field_step                 # Interval steps can be specified.
-    range: 1-10:2, 1-2:0.1            # 1,3,5,7,9,1, 1.1,1.2...,2
+  - field: field_step                   # Interval steps can be specified.
+    range: 1-10:2, 1-2:0.1,9-1:-1       # 1,3,5,7,9,1, 1.1,1.2...,2,9,8,7,...,1
     postfix: "\t"
 
-  - field: field_random               # Use R to specify randomly. Set either R or a specified step.
-    range: 1-10:R                     # 1,5,8...
+  - field: field_random                 # Use R to specify randomly. Set either R or a specified step.
+    range: 1-10:R                       # 1,5,8...
     postfix: "\t"
 
-  - field: field_file                 # Read a list from a file and set it as random.
-    range: users.txt:R                # Using the lines of users.txt as range and set it as random.
+  - field: field_file                   # Read a list from a file and set it as random.
+    range: users.txt:R                  # Using the lines of users.txt as range and set it as random.
     postfix: "\t"
 
   - field: field_loop                   # Self-loop field.