When do you pronounce ending sound of "s" as /s/, /z/?

Answer 1

I assume you are referring to root forms that add an -s (or -es) to a "root" form as with:
1) noun
....a) common plural ending (/s/=maps, /z/=streams, faces)
....b) common possessive ending (/s/ =book's, /z/=man's, face's)
2) verb -- present tense, third person singular ending
(/s/ =makes, /z/ =adds, dresses)

Note in the examples above, the final 's' unvvoiced (/s/) whenever the sound preceding it is unvoiced, but voiced (/z/) if the sound preceding (whether a consonant [2nd example in each set] or vowel** sound [final example in each a set]) is voiced

**note that English vowel sounds are ALWAYS voiced

Answer 2

Actually, bruhaha left one out. There are three ways to pronounce the ending.

[s]: following voiceless sounds
[z]: following voiced consonants except [z], [s], "sh", and "ch"
[ez]: following [s], [z], "sh", and "ch"
(actually, the vowel in the previous one is a schwa, but there isn't an ASCII character for that)

I hope this helps! I think I remembered it accurately.

Answer 3

When you come upon the wordz that reguire you too.

Answer 4

go to thefreedictionary.com and they will let you know what you need to know hehe

Answer 5

please, use, has, ...