Lesson 29 In vs. On
Prepositions are very tricky. Even when you think you understand the difference between in and on, you can still make errors like Mami does.
Joanne: Hi, Mami. Did you enjoy your trip to Canada? Did you take many photos?
Mami: Yes, I had a great time. I took lots of photos, but they’re all in my computer.
Mami said “in my computer” not “on my computer” because she knows “in” describes containment, and the computer contains her photos. So why is she wrong? Because “on” describes flat surfaces. Computer screens are flat, so we say photos are on a computer. “In a computer” describes physical technology like the drives and processors that are actually inside a computer. So remember, anything you see on a screen is on a computer. The same rule holds for TVs.