CBS has unveiled that “ Big Brother ” Season 28 premieres on July 9 at 8 p.m. ET/PT. The show’s companion series, “Big Brother: Unlocked,” returns the following day in the same time slot. After the Season 28 premiere, subsequent episodes will air Wednesdays and Thursdays at 8 p.m. ET/PT, while the live evictions will be on Sundays at 8 p.m. ET/PT. CBS promises “Big Brother” Season 28 will feature “the most programming hours ever.” The show will also debut its 1,000th episode during the new