Final answer:
An example of an informal sentence in English is: 'Gonna grab some lunch.'
Step-by-step explanation:
An example of an informal sentence in English is: 'Gonna grab some lunch.' The word 'gonna' is a colloquial contraction of 'going to' and is commonly used in informal speech. The use of contractions and informal language ('grab some lunch') makes this sentence an example of informal English.
Learn more about informal English