polish

Author: Martijn Hoekstra

_tour/multiple-parameter-lists.md

@@ -38,6 +38,7 @@ Suggested use cases for multiple parameter lists include:
 
 #### Drive type inference
 
+It so happens that in Scala, type inference proceeds one parameter list at at time.
 Say, you have the following method:
 
 ```tut
@@ -57,14 +58,14 @@ def firstWay = foldleft1[Int, Int](numbers, 0, _ + _)
 def secondWay = foldleft1(numbers, 0, (a: Int, b: Int) => a + b)
 ```
 
-That's because scala won't be able to infer the type of the function `_ + _`, as it's still inferring `A` and `B`. By moving the paramter `op` to its own parameter list, `A` and `B` have been inferred, and `_ + _` will match the the inferred type `(Int, Int) => Int`
+That's because scala won't be able to infer the type of the function `_ + _`, as it's still inferring `A` and `B`. By moving the parameter `op` to its own parameter list, `A` and `B` are inferred in the first parameter list. These inferred types will then be available to the second parameter list and `_ + _` will match the the inferred type `(Int, Int) => Int`
 
 ```tut
 def foldleft2[A, B](as: List[A], b0: B)(op: (B, A) => B) = ???
 def possible = foldleft2(numbers, 0)(_ + _)
 ```
 
-This definition doesn't need any type hints, and can infer all of its parameters.
+This definition doesn't need any type hints and can infer all of its parameters.
 
 
 #### Implicit parameters