Fix grammar

Author: jonathanlu31

2-ui/2-events/04-default-browser-action/article.md

@@ -17,7 +17,7 @@ There are two ways to tell the browser we don't want it to act:
 - The main way is to use the `event` object. There's a method `event.preventDefault()`.
 - If the handler is assigned using `on<event>` (not by `addEventListener`), then returning `false` also works the same.
 
-In this HTML a click on a link doesn't lead to navigation, browser doesn't do anything:
+In this HTML, a click on a link doesn't lead to navigation; the browser doesn't do anything:
 
 ```html autorun height=60 no-beautify
 <a href="/" onclick="return false">Click here</a>
@@ -96,7 +96,7 @@ That's because the browser action is canceled on `mousedown`. The focusing is st
 
 The optional `passive: true` option of `addEventListener` signals the browser that the handler is not going to call `preventDefault()`.
 
-Why that may be needed?
+Why might that be needed?
 
 There are some events like `touchmove` on mobile devices (when the user moves their finger across the screen), that cause scrolling by default, but that scrolling can be prevented using `preventDefault()` in the handler.