Add "g", and I may end early in the morning.
Add "b", and I may end late in the afternoon.
Add "t", and you better listen while you do it.
Add "y", and it can come in a bundle.
Answers should be in the form
followed by your explanation.
Answer : JO_
JOG - people generally prefer jogging early in the morning
JOB - work started in the morning may take up entire afternoon
JOT - while noting down important details from boss/teacher they expect us to pay attention to what they are saying
JOY - new born baby is also referred to as a bundle of joy