Texthelp Read and Write: literacy support software- includes text to speech. This allows you to listen at the same time as reading. Its a good way to review your written assignments, you can more easily recognise incomplete sentences and identify wrong word choice.
Texthelp also has useful dictionaries and a Verb checker. Type in the verb you would like to revise and texthelp will give examples of the different verb forms for that verb, past, present or future.