A gerund (verb + ing) acts like a noun in a sentence.

• Seeing is believing.
• Running a marathon is not an easy thing to do.
• Watching TV is sometimes harmful.
• Eating is always fun.
• My hobby is painting.
• She loves babysitting her sister.
• I like listening to music.
• I wasted all my afternoon by taking a nap.
• I am afraid of singing a song on a stage.

 Often, a possessive noun or pronoun comes before a gerund.

• I hope that you don’t mind my using your pen.
• Don’t be mad about my leaving early.
• I don’t want you misunderstanding.
• You will be amazed by my writing.