Among the points covered in last week’s post was the difference between outside and outside of. That brief explanation was your appetizer. Now let’s see how you handle the full course by making nine choices involving prepositions followed by of.
1. Phil led his family inside/inside of the cave.
2. Lil usually gets to her office inside/inside of 30 minutes.
3. Despite the wind, the parachutist managed to land inside/inside of the circle.
4. No one on our staff outside/outside of Will speaks Spanish.
5. Jill delivered her news report from outside/outside of the Capitol.
6. Gil applied at every mall business outside/outside of the eateries.
7. The manager took 20 percent off/off of my check because of the slow service.
8. The kids had a ball jumping off/off of the sand dunes.
9. Let’s move off/off of this discussion so we can get to our final item.
Using of after another preposition is almost always incorrect, but inside of and outside of have special meanings. Inside of means less than (as in #2). Outside of means except or except for (as in #4 and #6). Off of is never correct. Therefore, we want of only in 2, 4, and 6.