All in Imperial measurements though.
Actually, not since 1824. In the United States, there is a system called 'Customary Units'. Metrication was resisted in the US in the late 19th Century partly on religious grounds.
Have a care when referring to units of measurement in a POH or Flight Manual originating in the US. You're fairly safe with the smaller units of length, though things get strange with longer distances. Units of mass for our purposes are mainly equivalent to the old Imperial units but units of volume are way off. The most glaring of these is a US gallon. Generally in the UK, we dispense fuel and oil in litres, so you need to know how to convert from litres to Imperial gallons and US gallons. As a very rough guide and probably good enough for a PPL Skills Test, one litre of AVGAS on an average day weighs 1.6lb. Hopefully in ground school you've touched on how this can change, principally with temperature. I like to say that 1 kilo is about 2.2lbs.
Another thing we tend to mix and match is Mass and Weight. At rest on the Earth's surface, they have a rough equivalence . The Mass of an object remains largely the same most places in the Universe, whereas weight is very changeable. Concorde in the cruise weighed measurably less than it would have done on he surface, due to its distance from the centre of the Earth, but its mass remained the same (for the instant the measurement might have been taken - in practice both were going down at a prodigious rate as fuel was burned!)
TOO