The next exercise has two chords, the G chord and the D7 chord. As there is a D note in both chords, you can keep your thumb in position when you change between the chords. This will make changing between G and D7 very easy.
In this song, the first note (D) of the lead-in and bar 2, also occurs in the left hand part. Be sure to play this note with your right hand. On the recording there are five beats to introduce this song.