The Present Tense
When something happens ona regular basis, the Present Tense is used. For example “I play the piano." “The sun sets in the west."
The “-ing" form of the verb is referred to as the Present Progressive Tense. It is used to express that something is happening, or is in progress at the present moment in time. For example: “I am playing the piano (right now)." “You are looking at me, while I’m playing the piano;" but “You come every Saturday to see me when I play the piano."
The form of the verb “to be" willbe used to ask a question about something in progress. For example if someone wanted to ask what am I doing, they would ask “What are you doing" or if they saw me cooking, they could say “I smell fish.Are you cooking fish?" My reply tothe first question could be “I am exercising," or to the second could be “Yes, you’re right. I am cooking fish." A negative reply to something in progress would be “No, I am not cooking fish," again with the use of the verb “to be."
Emphatic form: do or does
If someone wants to ask me if I play the piano, they would ask “Do you play the piano?" and I would reply “Yes, I do" or, if I didn’t, “No, I don’t" or “No I do not." The word do is used for emphasis, and is also the way to ask a question of someone as to whether he does something on a regular basis or not. “Does she care for him?" The answer: “Yes, she does care." An example of the negative with “does" is “She does not (doesn’t) care for him".