EBS Lesson Nine Developing root and fifth
Figure 1. Notes learned so far: A, C, D, E and G (Enlarge)
Figure 2. The bass note of B on the A string

Figure 3. The bass note of F on the D string

Figure 4. The low bass note of F on the E string

Worth four beats.
In Exercise 7, you will see a note that is new to you. This is a whole note.