Acres is one example. 640 acres = a square mile. A mile is also a carryover from the imperial system. When Canada transferred over to the metric system, they found that the old system had to stay in place, otherwise all the surveying would have to be redone. There are two examples in this paragraph, but here's another as a bonus.
The Car dealerships in Canada still use the Imperial Gallon to describe how many miles per gallon you might get with the particular car you are looking at. When we bought our Honda Fit, the dealership told us we would get 50 miles / gallon, and they were not lying. It get's a little less now but we are doing more city driving. And who knows what additives are put in the gasoline. The reason the dealerships do this is because the Imperial Gallon is larger than a US gallon. So for every gallon burned you get more miles with an imperial gallon than you do with a US gallon. That's why you learn to convert. Can't let people trick you.
