1.1 We can use the affirmative form for example:
I work = I work for an IT company.
You work= You work hard everyday.
He/she/it works= She works at the hospital on weekends.
He works during weekends most of the time.
It works very well still.
We work = We work during the holidays.
They work= They work hard to finish the presentation next week.
2. Spelling of third person singular forms changes
2.1 Most verbs add –s to infinitive
Shop-shops = She shops during her holidays.
Stay-stays = She stays in the office for the conference.
Work-works= He works at the food and beverage industry.
2.2 Verbs ending in consonant +y : change y to i and add es
Copy- copies = Thelma says to make 100 copies of the document.
Hurry- Hurries= He hurries to the office because he has an emergency meeting to attend.
But vowel + y=
Enjoy-enjoys= She enjoys her 5-day vacation in her hometown.
2.3 Verbs ending in –s,-z,-ch,-sh or –x add –es to infinitive
Miss-misses= She misses her son a lot bec. she’s on a business trip now.
Catch-catches= He is very happy because he catches the last train for this morning.
2.4 There are exceptions to the rules too like:
Have-has= She has to make reports today.
Go-goes- He goes to the office very early.
Do-does- They do consider your suggestions.
3. Pronunciation of third person singular forms depends on the nouns that comes before it. The rules are the same for the plural –es and some irregular pronunciation like says ( sez)..etc.