diff --git a/docs/document/Powershell/docs/Language/String.md b/docs/document/Powershell/docs/Language/String.md
index 23e95c05..aa4023aa 100644
--- a/docs/document/Powershell/docs/Language/String.md
+++ b/docs/document/Powershell/docs/Language/String.md
@@ -114,6 +114,7 @@ Exception will be raised if conversion failed.
 ```ps1
 'Janet is a girl' -match 'Jane' # True
 'Janet is a girl' -replace '^Janet', 'Jane'
+'Janet is a girl' -replace '^Janet', 'Jane' -replace 'is', 'is not' # replace multiple times inline.
 ```
 
 All previous matches and captured groups can be accessed in `$matches` builtin variable.
diff --git a/docs/document/Powershell/docs/Object Manipulation/Extended Type System.md b/docs/document/Powershell/docs/Type System/Extended Type System.md
similarity index 95%
rename from docs/document/Powershell/docs/Object Manipulation/Extended Type System.md
rename to docs/document/Powershell/docs/Type System/Extended Type System.md
index 64433b4a..4ecd200b 100644
--- a/docs/document/Powershell/docs/Object Manipulation/Extended Type System.md	
+++ b/docs/document/Powershell/docs/Type System/Extended Type System.md	
@@ -12,7 +12,6 @@ A common example would be `Process` type.
 ```ps1
 (gps | select -First 1).GetType().Name # Process
 (gps | select -First 1) -is [PSObject] # True
-(gps | select -First 1) -is [PSCustomObject] # True
 # -is checks underlying type too
 (gps | select -First 1) -is [System.Diagnostics.Process] # True
 ```
@@ -24,6 +23,8 @@ The functionality of ETS achieved benifits:
 - Accessibility to the underlying object.
 - Manipulation on extended members.
 
+## What's `PSObject`
+
 ## ETS Members
 
 To represent meta of ETS members, Powershell has an abstract class called `PSMemberInfo`, each concrete member info type is derived from it.