Update README.rst

README.rst

@@ -49,7 +49,7 @@ scikit-learn is tested to work under Python 2.6, Python 2.7, and Python 3.4.
 `six <http:https://pythonhosted.org/six/>`_). It should also work with Python 3.3.
 
 The required dependencies to build the software are NumPy >= 1.6.1,
-SciPy >= 0.9 and a working C/C++ compiler. For a development version,
+SciPy >= 0.9 and a working C/C++ compiler. For the development version,
 you will also require Cython >=0.23.
 
 For running the examples Matplotlib >= 1.1.1 is required and for running the