Present Continuous : I am doing.

 Present Continuous : I am doing

                                                                    She's eating.    She isn't reading

It's raining. The sun isn't shining.

They're running. They aren't walking.

The present continuous is am/is/are + doing/eating/running/writing, etc.

- I'm working. I'm not watching TV.

- Chris is taking a bath.

- She isn't eating. ( or She's not eating)

- The phone is ringing.

- We're having dinner.

- You're not listening to me. ( or You aren't listening to me.)

- The children are doing their homework.

B: am/is/are + V.ing = something is happening now.

    (V.ing = Verb + ing) 

- Please be quiet. I'm woring. (=I'm working now.)

- Look at Michikol. She's wearing her new hat. (=she's wearing it now.)

- The weather is nice. It's not raining.

- "Where are the children?" "They're playing in the park."

- (on the phone) We're having dinner now. Can you call back later?

- You can turn off the television. I'm not watching it.

ตัวอย่างการเขียน Verb เติม ing 

come → coming

write → writing

dance → dancing

run → running

sit → sitting

awim → awimming

lie → lying

Reference : Basic Grammar in use