Based on, based off, based in, based out of...people are changing the way they use prepositions with "based." Also, people can get overzealous about deleting every "that" they can find in a sentence. Here's why you need it sometimes. FOLLOW GRAMMAR GIRL Twitter: http://twitter.com/grammargirl Facebook: http://facebook.com/grammargirl Pinterest: http://pinterest.com/realgrammargirl Instagram: http://instagram.com/thegrammargirl LinkedIn: https://www.linkedin.com/company/grammar-girl GRAMMAR POP Optimized for iPad: https://itunes.apple.com/us/app/grammar-pop-hd/id666851934?mt=8&ign-mpt=uo%3D4 For all iOS Devices: https://itunes.apple.com/us/app/grammar-pop-hd/id666851934?mt=8&ign-mpt=uo%3D4 GRAMMAR GIRL BOOKS http://www.quickanddirtytips.com/grammar-girl-book-page THE GRAMMAR DAILY 2018 CALENDAR http://amzn.to/2f8jPDG Grammar Girl is part of the Quick and Dirty Tips podcast network. Check out all the Quick and Dirty Tips shows: www.quickanddirtytips.com/podcasts