Grandpa's Sister / Synchronized Swimming - S4-E12
Continuity mistake: Synchronized Swimming: In the pool scene at the beginning, we see a close-up shot of Connie and Maria. In the next shot, they are nowhere to be found. The three kids surrounding the pool in the beginning also disappear. (This happens because the opening shots are reused from the episode "Sixth Grade Girls.") (00:12:01)
Answer: The show is based in present day times. Plus most cars aren't old fashtioned, I recall seeing a limo and not to mention a cherry picker, etc.