According to scientists, our mental abilities begin to _______ from the age of 27 after reaching the highest level at 22．

According to his letter,he had to _______ his affairs in Paris before he could return home．

--- You should apologize to Chris as soon as possible. --- No way! It was not my ____. 

-- Oh, it’s lunch time. I am a little hungry.-- Let’s go. It’s my ________.

 You needn't have apologized for your absence—________， it's hardly your fault.