Merge pull request #10739 from m4jing/patch-4

fix typos

docs/manual/introduction/Useful-links.html

@@ -51,7 +51,7 @@
 			</li>
 		 <li>
 			 [link:https://www.udacity.com/course/cs291 Interactive 3D Graphics] - a free course on Udacity that teaches the fundamentals of 3D Graphics,
-			 and uses three.js as it coding tool.
+			 and uses three.js as its coding tool.
 		 </li>
 		 <li>
 			[Link:https://aerotwist.com/tutorials/ Aerotwist] tutorials by [link:https://github.com/paullewis/ Paul Lewis].
@@ -81,7 +81,7 @@
 		<ul>
 			<li>
 				[link:http://threejsdoc.appspot.com/doc/index.html threejsdoc] - less descriptive than the official docs here, however this is
-				useful because it links every API element to to every official three.js [link:https://threejs.org/examples/ example] that uses it.
+				useful because it links every API element to every official three.js [link:https://threejs.org/examples/ example] that uses it.
 			</li>
 			<li>
 				[link:http://ushiroad.com/3j/ Three.js walking map] - a graphical breakdown of the structure of a three.js scene.
@@ -97,7 +97,7 @@
 				[link:http://www.reddit.com/r/webgl/ WebGL on reddit]
 			</li>
 			<li>
-				[link:http://learningwebgl.com/blog/ Learning WebGL Blog] – The authoritaive news source for WebGL.
+				[link:http://learningwebgl.com/blog/ Learning WebGL Blog] – The authoritive news source for WebGL.
 			</li>
 			<li>
 				[link:https://plus.google.com/104300307601542851567/posts Three.js posts] on Google+ – frequent posts on Three.js