Learn present simple tense rules and usage
I/You/We/They: verb (base form)
• I work in an office.
He/She/It: verb + s/es
• She works in an office.
I/You/We/They: don't + verb
• I don't like coffee.
He/She/It: doesn't + verb
• He doesn't like coffee.
I/You/We/They: Do + subject + verb?
• Do you speak English?
He/She/It: Does + subject + verb?
• Does she speak English?
Wrong: He don't like pizza.
Use "doesn't" with he/she/it
Correct: He doesn't like pizza.
Perfect! Third person singular uses "doesn't"