Websites that provide English question and answer tests include ihBristol.com and Englishjet.com. All questions are multiple choice, and instant feedback is available by clicking on Submit Answers or Test Results. Both websites are free as of January 2016.
Sharpen vocabulary and grammar skills by taking tests at ihBristol.com. Click the link titled Grammar, Vocabulary & Phrases to display a page on which you may practice English at three different levels: Elementary, Intermediate and Advanced. Access more exercises by creating a free online account.
Alternatively, practice English grammar at Englishjet.com. The website offers online courses for which students are awarded certificates upon successful completion.