Given below hope it helps!
Step-by-step explanation:
The steps for changing from plural to singular are:
If there is an (s) after the word remove
If there is an ies after the word remove and add y
If there is ves remove and add f or fe
However there are a few exceptions and I will point it out in the -
1) body
2) joy
3) loaf
4) coolie
(In this cooly won't make sense so we just remove the s)
5) key
6) bush
7) sheep
(The singular of sheep is also sheep)
8) watch
9) storey
10) ray
11) foot
(The singular is foot because no other rule applies to this word, this is an exception)
12) wife
13) child
(This is an exception too where we remove ren)
14) lily
15) fairy