Typo fixes

doc/tutorial/using_gpu.txt

@@ -284,13 +284,13 @@ Tips for Improving Performance on GPU
   Check the line similar to *Spent Xs(X%) in cpu op, Xs(X%) in gpu op and Xs(X%) in transfer op*.
   This can tell you if not enough of your graph is on the GPU or if there
   is too much memory transfer.
-* Use nvcc options. nvcc support those options to speed up some
+* Use nvcc options. nvcc supports those options to speed up some
   computations: `-ftz=true` to `flush denormals values to
   zeros. <https://developer.nvidia.com/content/cuda-pro-tip-flush-denormals-confidence>`_,
-  `--prec-div=false` and `--prec-sqrt=false` option to speed up
+  `--prec-div=false` and `--prec-sqrt=false` options to speed up
   division and square root operation by being less precise. You can
-  enable all of them with with the `nvcc.flags=--use_fast_math` Theano
-  flags or you can enable them individually as in this example
+  enable all of them with the `nvcc.flags=--use_fast_math` Theano
+  flag or you can enable them individually as in this example:
   `nvcc.flags=-ftz=true --prec-div=false`.
 
 .. _gpu_async: