Update task.md

language checked

oldSchoolServer/oldSchoolServerGroupBy/task.md

@@ -1,18 +1,18 @@
 In Kotlin, you can work with collections in a different way.
-You can perform not only basic operations like sorting or finding some elements,
+You can perform not only basic operations, like sorting or finding some elements,
 but also more complex ones.
 One such operation is _grouping_ items by a condition.
 
 The easiest way to group elements is to use the built-in [`groupBy`](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/group-by.html) function.
 
 This function allows you to group elements of the original collection by the 
-key returned by the given `keySelector` function applied to each 
+key returned by the given `keySelector` function, which is applied to each 
 element and returns a map where each group key is associated with a list of corresponding elements.
 
 In simple words, if you group objects, for example, by their length, 
 then the keys in the resulting map will be the possible length 
-values found in the original collection, and for each such key a 
-list of objects from the original collection of a given length will be compiled.
+values found in the original collection, and for each such key, a 
+list of objects from the original collection with a given length will be compiled.
 
 Consider an example:
 ```kotlin
@@ -25,7 +25,7 @@ fun main() {
 }
 ```
 
-This code will print into the console the following output since we group the strings from the list by their length:
+Since we group the strings from the list by their length, this code will print into the console the following output:
 ```text
 Current length is 1. The words: a
 Current length is 3. The words: abc, def