31.3.1 Comparative - Superiority

The comparative of superiority is formed with the comparative form (ending -er) and the particle als (= than).

  31.3.1.1 ... of adjectives

Some examples      
    comparative form particle  
He is   lazier than she is.
Er ist   fauler als sie.
His car was   more expensive than mine.
Sein Auto war   teurer als meines.