i have a doubt of infinitives and gerunds question.
Write a second sentence for the given sentence using the words in bracket.
1.By chance I saw your uncle. bracketed word-happened

The noun made by adding ing to a verb is known as gerund. For example: a) Swimming is a good exercise. b) Smoking killed him.
The 'to' form of a verb is known as infinitive. For example: a) To study is important for every student. b) She wanted to go.
1. I happened to see your uncle.