In some musical situations, it sounds good to sustain one chord while the bass plays a line underneath it. The chord symbols change every two beats, but the guitar part on the recording is simply a C triad. The changing symbols indicate the moving bass part which descends through the C major scale. Try this process on the guitar and listen to each new bass note change the effect of the chord.
C Triad over Descending C Major Scale
This technique can be used with any type of chord in both major and minor keys. In this example, a Cm triad is played over a bass line which descends through the key of C minor. Both the natural and flattened 7th degrees are used in the bass line.
Cm Triad over descending C min Hybrid Scale