Update article.md

Author: iliakan

1-js/11-async/08-async-await/article.md

@@ -250,7 +250,7 @@ async function f() {
 f();
 ```
 
-If we don't have `try..catch` and a promise generated by the call of the async function `f()` becomes rejected. We can append `.catch` to handle it:
+If we don't have `try..catch`, then the promise generated by the call of the async function `f()` becomes rejected. We can append `.catch` to handle it:
 
 ```js run
 async function f() {