If the vehicle's gas mileage decreases as the oil gets dirtier, we will notice a trend of less mileage throughout the trials.
(the vehicle's gas mileage; decreases; T:as the oil gets dirtier) (the oil; gets; dirtier) (we; will notice; a trend of less mileage throughout the trials)
the vehicle's gas mileage the oil we
decreases gets will notice
T:as the oil gets dirtier
dirtier
a trend of less mileage throughout the trials