fix grammar typo
removed repeated 'for'
diff --git a/docs/coroutines-guide.md b/docs/coroutines-guide.md
index 7ccbca8..8756246 100644
--- a/docs/coroutines-guide.md
+++ b/docs/coroutines-guide.md
@@ -2,7 +2,7 @@
Kotlin, as a language, provides only minimal low-level APIs in its standard library to enable various other
libraries to utilize coroutines. Unlike many other languages with similar capabilities, `async` and `await`
are not keywords in Kotlin and are not even part of its standard library. Moreover, Kotlin's concept
-of _suspending function_ provides a safer and less error-prone abstraction for for asynchronous
+of _suspending function_ provides a safer and less error-prone abstraction for asynchronous
operations than futures and promises.
`kotlinx.coroutines` is a rich library for coroutines developed by JetBrains. It contains a number of high-level
@@ -29,4 +29,4 @@
* [Guide to UI programming with coroutines](../ui/coroutines-guide-ui.md)
* [Guide to reactive streams with coroutines](../reactive/coroutines-guide-reactive.md)
* [Coroutines design document (KEEP)](https://github.com/Kotlin/kotlin-coroutines/blob/master/kotlin-coroutines-informal.md)
-* [Full kotlinx.coroutines API reference](http://kotlin.github.io/kotlinx.coroutines)
\ No newline at end of file
+* [Full kotlinx.coroutines API reference](http://kotlin.github.io/kotlinx.coroutines)