typos (#59)

diff --git a/lib/src/benchmark_base.dart b/lib/src/benchmark_base.dart
index b47167d..2165828 100644
--- a/lib/src/benchmark_base.dart
+++ b/lib/src/benchmark_base.dart
@@ -18,7 +18,7 @@
     run();
   }
 
-  // Exercices the benchmark. By default invokes [run] 10 times.
+  // Exercises the benchmark. By default invokes [run] 10 times.
   void exercise() {
     for (var i = 0; i < 10; i++) {
       run();
@@ -28,10 +28,10 @@
   // Not measured setup code executed prior to the benchmark runs.
   void setup() {}
 
-  // Not measures teardown code executed after the benchark runs.
+  // Not measures teardown code executed after the benchmark runs.
   void teardown() {}
 
-  // Measures the score for this benchmark by executing it repeately until
+  // Measures the score for this benchmark by executing it repeatedly until
   // time minimum has been reached.
   static double measureFor(Function f, int minimumMillis) {
     var minimumMicros = minimumMillis * 1000;