Update 001. Basic Usage.md

tutorials/001. Basic Usage.md

@@ -51,7 +51,7 @@ When you are done with your simulation, don't forget to free the memory allocate
 
     Delete(world);
 
-Because dmech doesn't use D's garbage collector to allocate its memory, it needs to be freed manually. Don't try to update the simulation of access bodies after the world was freed. 
+Because dmech doesn't use D's garbage collector to allocate its memory, it needs to be freed manually. Don't try to update the simulation or access bodies after the world was freed. 
 
 You can use dlib's ownership mechanism (`dlib.core.ownership`) to attach the world to some owner object, like your application or data manager: