Alcohols have a fairly broad feature between 3200 and 3500 cm-1 but no feature near 1700 cm-1.
Aldehydes and ketones have a feature near 1700 cm-1 but no significant features in the 2500 to 3500 cm-1 region.
Carboxylic acids have a very broad feature between 2500 and 3300 cm-1 and a feature near 1700 cm-1.