Add the word 'a' to 'whole seven seconds' to complete sentence (#2757)

content/docs/concurrent-mode-patterns.md

@@ -507,7 +507,7 @@ function ProfileTrivia({ resource }) {
 
 **[Try it on CodeSandbox](https://codesandbox.io/s/focused-mountain-uhkzg)**
 
-If you press "Open Profile" now, you can tell something is wrong. It takes whole seven seconds to make the transition now! This is because our trivia API is too slow. Let's say we can't make the API faster. How can we improve the user experience with this constraint?
+If you press "Open Profile" now, you can tell something is wrong. It takes a whole seven seconds to make the transition now! This is because our trivia API is too slow. Let's say we can't make the API faster. How can we improve the user experience with this constraint?
 
 If we don't want to stay in the Pending state for too long, our first instinct might be to set `timeoutMs` in `useTransition` to something smaller, like `3000`. You can try this [here](https://codesandbox.io/s/practical-kowalevski-kpjg4). This lets us escape the prolonged Pending state, but we still don't have anything useful to show!