“Remember that sketchy neighborhood we used to live in?”
You're talking with an old college friend. You're remembering old times together. In college, you and your friend were poor so you lived in a cheap house in a dangerous part of town. You remind him of this.
Remember that sketchy neighborhood we used to live in?
You "live in" a country, a state, province or prefecture, a city, or a neighborhood:
I used to live in Canada.
She lives in Beverly Hills.
Sometimes you can use "live on" for explaining which side of a city you live in:
I live on the South side of Chicago.
You live at a specific address:
I live at 112 West Crescent Street.
In casual speech, you can ask someone "Remember ___?" instead of "Do you remember ___?"
You ask this question to ask whether someone remembers an experience that you had together. For example:
Remember that time when we went camping and forgot to bring a tent?
You don't usually ask "Remember ___?" to find out whether someone remembers facts like this:
Do you remember his phone number?
A "sketchy" neighborhood looks like it might be dangerous. Often a sketchy neighborhood has old buildings that need to be repaired. There might also be people there who look violent or sneaky.
If you're sure that a neighborhood is dangerous, you usually don't call it "sketchy". Instead, call it "a bad neighborhood" or "a rough neighborhood".
Other things that you can describe as "sketchy" include:
- a hotel
- a bar or night club
- a person