I) Present Tense

(a) Simple Present : This Tense is used to express the habits, daily routine and universal truths. In this tense the first form of the verb is used.

Taking the verb ‘eat’ we can make sentences in the following manner :

The formula for simple present is Subject + V1

I eat an apple everyday.
We eat apples everyday.
You eat apples everyday.
He eats an apple everyday.
She eats an apple everyday.
It eats an apple everyday.
They eat apples everyday.

(b) Present Continuous : This Tense is used to express an action which is continuing or taking place now. In this tense the ‘ing’ form of the verb is used.

The formula for present continuous is Subject + Aux +V4 (ing form)

I am eating an apple now.
We are eating apples now.
You are eating an apple now.
He is eating an apple now.
She is eating an apple now.
It is eating an apple now.
They are eating apples now.

(c) Present Perfect : This Tense is used to express an action which is over just now or completed today. In this tense the third form of the verb is used.

The formula for present perfect is Subject +Auxiliary Verb + V3 (Past Participle Form)

I have eaten an apple today.
We have eaten apples today.
You have eaten an apple today.
He has eaten an apple today.
She has eaten an apple today.
It has eaten an apple today.
They have eaten apples today.

(c) Present Perfect Continuous : This Tense is used to express an action which began at some point of time in the past and is still continuing. In this tense the ‘ing’ form of the verb is used.

The formula for present perfect continuous is Subject+Aux+Aux+V4(ing form)

I have been eating apples for the last three months.
We have been eating apples for the last three months.
You have been eating apples for the last three months.
He has been eating apples for the last three months.
She has been eating apples for the last three months.
It has been eating apples for the last three months.
They have been eating apples for the last three months.