In English, the suffix "-ing" is added to verbs to form the present participle or the gerund. Here are the main cases when you would use "-ing" in an English verb:

1. Continuous/Progressive Tenses: The "-ing" form is used to construct continuous or progressive tenses. For example:

   • "She is studying for her exams." (present continuous)
   • "I was reading a book when the phone rang." (past continuous)
   • "They will be eating dinner at 8 o'clock." (future continuous)

2. Gerunds: A gerund is a verb form that functions as a noun in a sentence. Gerunds are used to talk about activities or actions as objects of a sentence. For example:

   • "I enjoy swimming in the ocean." (Swimming is the object of the verb "enjoy.")
   • "Her hobby is painting." (Painting is the subject complement.)
   • "He apologized for being late." (Being is the object of the preposition "for.")

3. Present Participles: Present participles are used in various ways, including as part of progressive tenses or as adjectives. For example:

   • "The running child caught the ball." (Running describes the child.)
   • "The laughing baby brightened everyone's day."
   ( laughing baby the baby.)
   • "The barking dog alerted the neighbors." (Barking describes the dog.)

It's worth noting that there are some irregular verbs in English that form their present participle differently, such as "go" (going) or "lie" (lying). Additionally, some verbs have different meanings when used in the present participle form, such as "I love running" (enjoying the activity) versus "I am running out of time" (performing the action).

1. I enjoy swimming in the ocean.
2. She is studying for her exams.
3. The barking dog alerted the neighbors.
4. They were talking about their vacation plans.
5. He apologized for being late.
6. Running is good for your health.
7. The laughing baby brightened everyone's day.
8. We will be eating dinner at 8 o'clock.
9. The setting sun painted the sky with vibrant colors.
10. I love cooking new recipes.
11. They appreciate her singing talent.
12. The chirping birds woke me up early.
13. She was dancing gracefully on the stage.
14. The children were playing in the park.
15. He enjoys playing the guitar in his free time.
16. The ongoing construction work is causing traffic delays.
17. The melting ice cream created a sticky mess.
18. We were waiting for the bus in the pouring rain.
19. The howling wind kept us awake all night.
20. Her constant complaining annoys everyone around her.