The following duet contains both staccato and slur marks. This means there are three different techniques used to play the various notes, i.e., ordinary tonguing, slurring, and staccato tonguing. These different ways of playing the notes are called articulations. Articulations are used to create a variety of expressions in music.
To play duets well, you need to be able to listen to yourself and the other player at the same time. Learn your part well and then try listening to both parts as you play.