Practice:
1. https://personal.colby.edu/~bknelson/SLC/DO1.php
2. http://www.studyspanish.com/practice/dopro1.htm
3. NEW! https://personal.colby.edu/~bknelson/SLC/DO1.php
4. NEW! https://www.conjuguemos.com/activity.php?id=44&source=public&language=spanish&type=fillin
5. NEW! http://www.bowdoin.edu/~eyepes/newgr/prcd.htm
6. NEW! http://www.learnspanishfeelgood.com/pronouns-direct-object2.html