fix some errors

index.html

@@ -4688,8 +4688,8 @@ <h2>Definition of Roles</h2>
 				</p>
 				<p>
 					The <code>listview</code> role does not assume any particular form of visual presentation.
-					A <code>listview</code> may scroll in any direction as  users move focus.</code>
-					Items may be arranged in a single column, a single row, or in multiple columns or rows.
+					A <code>listview</code> can scroll in any direction as  users move focus.</code>
+					Items can be arranged in a single column, a single row, or in multiple columns or rows.
 					Authors SHOULD indicate whether the order of the collection is presented horizontally or vertically with <pref>aria-orientation</pref>.
 					For example, if a set of twenty cards is presented in a vertical list that is wrapped into five columns that contain four cards, authors SHOULD set <pref>aria-orientation</pref> to <code>vertical</code>.
 					This would inform assistive technology users that moving focus with the down arrow key would move focus from the first card to the second card whereas pressing the right arrow key (if supported) would move focus from the first card to the fifth card.
@@ -4750,7 +4750,7 @@ <h2>Definition of Roles</h2>
 						<td class="role-properties">
 							<ul>
 								<li><pref>aria-multiselectable</pref></li>
-								<li>aria-orientation</li>
+								<li><pref>aria-orientation</pref></li>
 							</ul>
 						</td>
 					</tr>
@@ -4801,7 +4801,7 @@ <h2>Definition of Roles</h2>
 				<p>
 					A <code>listviewitem</code> <a>element</a> can contain a nested collection of <code>listviewitem</code> elements.
 					A nested collection of <code>listviewitem</code> elements is enclosed in an element with the <rref>group</rref> <a>role</a>.
-					Authors may enable users to control the visibility and focusability of a nested collection, i.e., make it expandable and collapsable.
+					Authors can enable users to control the visibility and focusability of a nested collection, i.e., make it expandable and collapsable.
 					If the nested group of <code>listviewitem</code> elements can be expanded and collapsed, authors MUST specify a value for <sref>aria-expanded</sref> on the <code>listviewitem</code that contains the group.
 				</p>
 				<p>Authors MUST ensure [=elements=] with <a>role</a> <code>listviewitem</code> are <a>accessibility children</a> of an element with <a>role</a> <rref>listview</rref> or an element with <a>role</a> <rref>group</rref> that is the <a>accessibility child</a> of an element with role <rref>listviewitem</rref>.</p>