Tense rule with example

A. Simple Present Tense
The Simple Present is used to express :
(i) A habitual action
(ii) A general truth
(iii) What is happening (in exclamatory sentences only)
(iv) An order or request.

B. Present Continuous Tense
(Is/am/ are + Verb + ing)
(i) In order to form the Present Continuous Tense, we add Present Participle
to is, am or are. The Present Participle is formed by adding ‘ing’ to the first form of the verb.
‘Is’ is used with he, she, it or Third Person Singular Noun, ‘am’ is used with T and ‘are’ is used with we, you, they and plural Nouns. .
Examples : She is singing a song.

C. Present Perfect Tense
(Subject + Has /have + III form of the verb)
(i) In the Present Perfect Tense the past participle (III)) form of the verb is used with has or have. ‘Has’ is added with third person singular subjects, as—‘he’, ‘she’, ‘if and ‘Have’ is added with T, ‘we’, ‘you’, ‘they and plural nouns.
He has won a prize.
You have insulted me.
I have taken the dose of medicine.

D. Present Perfect Continuous Tense
(Subject + has /have + been + I form of the Verb + trig…)

In order to form the Present Perfect Continuous Tense, we put has been or have been before the Present Participle Form of the Verb ; as—
It has been raining for two hours.
I have beenjlying a kite since 2 O’clock.
(a) The Present Perfect Continuous Tense is used to describe an action that began in the Past, is still continuing and may extend into the Future ; as—
She has been waiting for you for three hours.
They have been playing cards since 10 A. M.