There are many kinds of suffixes in English language, e.g. /-s/, /-es/, /-d/, /-ed/, /-ing/, etc. All the suffixes have their own rules. For non native speakers, sometimes, we get difficult of which the suffix or the apostrophe /s/ should be used.
Compare this following example:
That is the desk's foot.
There are five desks in the classroom.
She likes my song.
He's the only one in my life.
From the sentences above, I do not mean to specify or to compare the two or more things which has far different in their own discussion. Here, I just want to discuss that, when we learn English we will find the "s" and will be a bad homework when we do not know what they are and when they are being used.
I try to classify the /s/ and I found 4 kinds of /s/ in English:
1. Apostrophe /s/
2. /s/ in plural noun.
3. /s/ as a suffix of verb in positive verbal of simple present tense.
4. /s/ as the abbreviation of verb "be" or auxiliaries.
Apostrophe "s"Apostrophe /s/ is used as possession or to express possessive status. It always refers to the property of a thing or noun.
This is your book. (/your/ is possessive adjective > your + noun)
This is Hendrick's book. (noun +/'s/ + noun)
Apostrophe /s/ at Hendrick's book indicates that the book belongs to Hendrick.
/s/ in plural noun
/s/ is also used to indicate plural noun. We then add /s/ or /es/ at the noun.
Those books are mine.
I have left 5 bundle of documents on the desk.
She has four watches in her collection.
/s/ as a suffix of verb in positive verbal of simple present tense.
/s/ is also used as a suffix in positive verbal of Simple present tense when the subject is /he/, /she/, /it/ or the similarity.
She calls me every day.
He phones me very often.
It eats meat.
Linda likes writing a piece of letter of love.
/s/ as the abbreviation of verb "be" or auxiliaries.
/s/ can be used to shorten the verb "be" or auxiliaries.
She's lonely. (She is)
He's my cousin. (He is)
It's a piece of cake. (It is)
You're the one I need. (You are)
They're late. (They are)
We're okay. (We are)
I'm fine. (I am)
AuxiliariesThey've gone. (/'ve/ = have)
She's been in Bali. (/'s/ = has)
You'd better get out now. (/'d/ = had)
We'd finished with it. (/'d/ = would)
I'd tell you the secret. (/'d/ = had)
He'll be mine. (/'ll/ = will or shall)
Notice that there are two apostrophe /d/ which are used in the example above. To make different which one stands for /would/ or /had/ will be discussed below:
1./'d/ for /had/ is used in Past perfect tense. We can see the use of the third verb or the past participle:
Had + Verb.III/past participle.
2./'d/ for /would/ is used when the verb is in the first verb or present verb:
Would +Verb.I/present verb.
3./'d/ for /had/ is also used specifically for the auxiliary /had better/. In this case, we can not change other parts for /better/ but /had/.