A Summary chart of verb tenses

II. using verb tenses

1. Simple present:

1. Water consists of oxygen and hydrogen.
2. Most animals kill only for food. (c) The world is round. The simple present says that something was true in the past, is true in the present, and will be true in the future. It is used for general statements of facts.
3. I study for two hours.
4. My classes begin at nine.
5. He always eats a sandwich for lunch.

   The simple present is used to express habitual or everyday activity.

6. I have a dollar right now.
7. I don't recognise that man.
8. He needs a pen right now.

   Certain verbs are not used in the progressive tenses. With the simple present may indicate a situation that exists right now, at the moment of speaking.

9. present progressive:

   John is sleeping right now.
10. I need an umbrella because it is raining.
11. John and Mary are talking on the phone.

    The present progressive expresses an activity that is in progress at the moment of speaking. It began in the recent past, is continuing at present, and probably will end at some point in the future.

12. I am taking five courses this semester.
13. John is trying to improve his work habits.
14. She is writing another book this year.

    Often the activity is of general nature: something generally in progress this week, this month, this year. Note (o): The sentence means that writing a book is a general activity she is engaged in at present, but it does not mean that at the moment of speaking she is sitting at her desk with a pen in her hand (or nowadays more likely before the keyboard of her computer).

Simple past:

1. I walked to school yesterday
2. He lived in Paris for ten years, but now he is living in Rome.
3. I bought a new car three days ago.