Directions: Each of the following sentences has word/words underlined. Identify which word class the underlined word/words belongs/belong to.

Swimming is a healthy exercise.

The word 'Swimming' is formed from the verb 'swim' by adding the suffix '-ing'. In the given sentence, it functions as a noun, acting as the subject of the verb 'is'. A verb form ending in '-ing' that functions as a noun is called a gerund.

Therefore, 'Swimming' is a gerund.

Answer: Gerund