The key to exercise solutions in chapter 4.5 - Grammar for the textbook Focus 3 - Student's Book with authors Daniel Brayshaw, Vaughan Jones, Bartosz Michałowski and Sue Kay from Pearson Education
Question
Use the prompts to write about things you will or won't have done by the end of today.
Answer
By the end of the day, I'll have eaten three or four pieces of fruits.