Following are some links to practice -ar present tense verb conjugations.
1. http://conjuguemos.com/home/docs/php/conjugator.php?language=spanish&id=1#top
choose ONLY –ar verbs from the list and All pronouns except vosotros
2. http://studyspanish.com/verbs/lessons/justar.htm
study the notes for –ar verbs , click on create a unique quiz, click on, no vosotros
3. or go straight to the quiz section and click on no vosotros
