Fix grammar error

README.md

@@ -30,7 +30,7 @@ catch {
 
 ## Advanced Zip
 
-For more advanced usage, Zip has functions that let you set custom  destination paths, work with password protected zips and use a progress handling closure. These function throw if there is an error but don't return.
+For more advanced usage, Zip has functions that let you set custom  destination paths, work with password protected zips and use a progress handling closure. These functions throw if there is an error but don't return.
 ```swift
 do {
     let filePath = NSBundle.mainBundle().URLForResource("file", withExtension: "zip")!