The use of plural – s in English has three different, but very regular phonological…

The use of plural –
s
in English has three different, but very regular phonological alternatives. We add /
s
/ to words like
bat, cook, cough
and
ship.
We add /
z
/ to words like
cab, cave, lad, rag
and
thing
. We add /?z/ to words like
bus, bush, church, judge
and
maze
.
·      Identify the sets of sounds that regularly precede each of these alternative pronunciations of the plural ending.
·      What features do each of these sets have in common?