Watch the Around the Corner online guitar lesson by Andrew Ford from 30 Rock Bass Grooves for Beginners You MUST Know
Groove 20 is in the style of "Up Around the Bend" by Creedence Clearwater Revival. It's a straight eighth note groove that really drives forward with those eighths. The chord changes are basically G to D, and then A for a full bar. Over the first D, we have a slash chord that has F# below the slash as our bass note. In Bar 1, we have 4 eighth notes on our root G, then move to four more eighths over our D with the F# chord. Then, we have our bar of A where it is all eighths but not all roots. There are 3 roots (or A's), then on our 4th eighth note, we move up to B on the "and" of beat 2. We continue with beat 3, playing a C#, the major 3rd, with the "and" of 3 going back down to B, and finally beat 4 plays our root A and we end with B.
The next bar is just straight eighths using roots for the G and D chords. Our last bar has a nice walk down starting on the root A for two eighths, down to G for two eighths, walking down to F# for 2, and finishing on E for 2 beats.