By functional group I mean an alcohol group or ketone group or aldehyde group or acid group.

官能团是指醇基或酮基或醛基或酸基。

Acetone has a ketone group and it's called 'acetone' because it was derived from acetic acid, which is vinegar, the most common carboxylic acid in your kitchen.

丙酮有一个酮基，之所以称为“丙酮”，是因为它是从醋酸中提取的，醋酸是厨房中最常见的羧酸。

Beta hydroxybutyric acid on the other hand, even though it's still one of the ketone bodies, isn't technically a ketoacid since its ketone group has been reduced to a hydroxyl group.

而β-羟基丁酸虽说也是酮体，但却不是酮酸，因为它的酮基团被还原成了羟基。

After that happens, the liver turns the fatty acids into ketone bodies, like acetoacetic acid and beta hydroxybutyric acid; acetoacetic acid is a ketoacid because it has a ketone group and a carboxylic acid group.

此后，肝把脂肪酸转化成酮体，比如乙酰乙酸、β-羟基丁酸；乙酰乙酸是一种酮酸，因为它有酮基团和羧酸基团。