Verb especially in simple present tense shows two types of situations;
- Static situation
- Dynamic situation
It is that situation in which verbal action seems to extend the moment it is uttered. Now see the following examples to let you understand.
- Max reads in Oxford College.
- Max drinks water.
Now in the first example (1) 3rd person singular form of the verb shows that Max is not only reading in Oxford College the moment we have uttered this sentence, rather it means that he has been reading and this continues up to now and even it will extend beyond that. The situation is extended. In the second example (2) the situation is quite different. An act of drinking water doesn't extend rather it is current to the utterance. It means Max is drinking water till this is uttered. This situation doesn't extend like the situation in first sentence.
So here we say that in the first example situation goes on even after we have uttered the sentence and also continued for certain time in past. Hence this situation is called static situation which doesn't change and remained the same (static).
In case of the second example (2) situation doesn't extend hence it is dynamic situation. We can add to it the words that indicate dynamic situation, like, "He drinks water right now." But if we use right now with the sentence that gives static situation it will be a bit awkward and therefore wrong expression, like, "Max reads in Oxford College right now." Language contains both situations and it means simple present tense also acts like continuous or perfect continuous in which verbal action continues even without using present participle.
Commentators are bound to use dynamic situation because they keep on telling what is going on now, not what shall remained the same for certain stretch of time whereas when we talk of person's living somewhere or reading in certain institutions we generally use static situation.