Exercise 35 contains a chord change between the F and G7 chords. As there is an F note in both chords, you can keep your second finger in the same position when you change between them. This will make changing between these two chords smoother and easier.
This is a half rest. The half rest has a value of 2 beats of silence.
This song contains several half rests. On the recording there are five beats to introduce this song.