I am buying a 98 Accord tommorrow. The only concern I have for it is, that when my dad checked the oil, it was way below the bottom line!

The car has 140,000km (Canada) on it, 3 yrs warrenty on engine. What would cause the oil engine to be reduced to be soo low? I will be doing a compression test on the car tomrrow. Anything else I should do to make sure that it doens't burn oil?