From 7107930a430f39587e263379069534400812c3ab Mon Sep 17 00:00:00 2001
From: zhongsp <patrick.zhongsp@gmail.com>
Date: Fri, 23 Aug 2019 12:04:01 +0800
Subject: [PATCH] "Variable Declarations.md" uses "?" before it is defined in
 "Functions.md". PR1029

---
 doc/handbook/Variable Declarations.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/doc/handbook/Variable Declarations.md b/doc/handbook/Variable Declarations.md
index 0cc3d73..7861029 100644
--- a/doc/handbook/Variable Declarations.md	
+++ b/doc/handbook/Variable Declarations.md	
@@ -561,6 +561,7 @@ function keepWholeObject(wholeObject: { a: string, b?: number }) {
 }
 ```
 
+此例中，`b?`表明`b`是可选的，因此它可能为`undefined`。
 现在，即使 `b` 为 undefined ， `keepWholeObject` 函数的变量 `wholeObject` 的属性 `a` 和 `b` 都会有值。
 
 ## 函数声明