Simple Present tense

most of students where english is foreign language have difficulties in tenses, including simple present tense. So, here i will explain simply about simple present tense.

What is simple present tense?
Simple Present is used to express the idea that an action is repeated or usual. The action can be a habit, a hobby, a daily event, a scheduled event or something that often happens. It can also be something a person often forgets or usually does not do.

the formula :

S + V1 (+ s/-es)
S + does not/ do not + V1

verb added s if the subject are first person or third person, e.g: I, they,we.
added by -es if the subject is second person, e.g: he, she, it.

However there are some verbs that can not added by s/es, so you have to look dictionary to check whether the verbs can be added by s/-es or not.

does not is used if the subject: he, she, it or singular noun.
do not is used if the subject: I, they, we or plural
eg:
* I play tennis.
* She does not play tennis.
* Does he play tennis?
* The train leaves every morning at 8 AM.
* The train does not leave at 9 AM.
* When does the train usually leave?
* She always forgets her purse.
* He never forgets his wallet.
* Every twelve months, the Earth circles the Sun.
* Does the Sun circle the Earth?