''The strong gongs groaning as the guns boom far'' illustrates

The phrase "The strong gongs groaning as the guns boom far" illustrates onomatopoeia. Onomatopoeia is a literary device that uses words that imitate the sounds they describe. In this case, the words "gongs," "groaning," and "guns" imitate the sounds of the objects they refer to, while the word "boom" describes the sound made by the guns. The use of onomatopoeia in this phrase helps to create a vivid and sensory image in the reader's mind of the sounds of war. It is a way to bring the reader closer to the experience being described and to make the language more evocative and engaging.