Minimal Pairs

/ð/ (voiced dental fricative)   and   /z/ (voiced alveolar fricative)
thenZen
clotheclose
bathebays
lathelaze
writherise
breathebreeze
titheties
seethesees
scythesize
withwhizz
boothbooze
teetheteas
Hythehighs
loathelows
soothesues