Fix a grammatical error in tutorial
@@ -33,7 +33,7 @@ The main difference of :class:`cupy.ndarray` from :class:`numpy.ndarray` is that
Its data is allocated on the *current device*, which will be explained later.
-Most of array manipulations are also do in the way similar to NumPy.
+Most of the array manipulations are also done in the way similar to NumPy.
Take the Euclidean norm (a.k.a L2 norm) for example.
NumPy has `numpy.lina.g.norm` to calculate it on CPU.
