So far only quarter notes and quarter note rests have been used. The next example is identical to the previous one in terms of note choices and timing. This time however the quarter note ( 3) followed by a quarter note rest (h) is replaced by a half note (g) which has a duration of two beats. The difference between a quarter note followed by quarter note rest and a half note is the sustained sound of the half note. Listen to the recording to get the right feel.
In the 2nd bar of example 20 which is in the key of G, the high G note is used as a root note variation and in the last bar a half note rest occurs which equals two beats of silence.
In the first bar of example 21 which is in the key of A the second note (low E down) is used as a variation instead of the usual 5th note up.
The half time feel for the rhythm with the root note and 5th as the note choice are the basis of many country bass lines. As illustrated in the examples above, the root note and/or 5th note can appear in different registers (*octaves) high or low.