Simple Present Tense

See the examples.

1. Whales are mammals.

2. A Tiger is a wild animal.

We also use simple present Tense to talk about events that happen regularly. The adverbs of time that show habitual actions are : always, usually, generally, often, sometimes, seldom, ever, and never.

See the following examples.

1. I always feed the animals and clean their cages.

2. We sometimes prepare food and drink d for the animals. 

In simple present tense, we use do/does and am/are/is for auxiliary verbs.

As subjects of sentences, pronouns I, You, We, They take the basic verb form (verb base). 

For pronouns He,She, It, we add an -s or -es to the end of the verb.

See the following examples .

Subject I, You, We, They

(+) Whales are mammals

(- ) Whales are not herbivores

(?) Are whales mammals ?

(+) I always feed the animals and clean their cages.

(-) I don't always feed the animals and clean their cages.

(?) Do I always feed the animals and clean their cages ?

Subjects He, She, It

(+) A Tiger is a wild animal.

(-) A Tiger is not a tame animal.

(?) Is a Tiger a wild animal ?

(+) He prepares food for the animals in the zoo

(-) He doesn't prepare food for the animals in the zoo

(?) Does he prepare food for the animals in the zoo ?