The questions that arise though this point in the play relate to Biff. Flashbacks raise questions about Biff's decisions at the end of his senior year in high school and about Biff's break with Willy.
When Willy visits Charley's office and talks with Bernard, Bernard tries to get answers to these questions.
Bernard asks Willy if years ago he told Biff not to go to summer school to make up the math class he flunked.
Bernard knows that Biff failed his math class and also knows that making up the class would have been easy for Biff, yet Biff decided not to do this. Bernard also knows that Biff was upset by something that happened in Boston when he went to visit his father on the road.
Bernard voices a question that the play will answer a later scene:
“What happened in Boston, Willy?”
The audience, at this point, does not have any knowledge of what happened in Boston and what led to the Biff's break with Willy. In the next scene, this information will be revealed.
Withholding information in this way helps to build tension in the play as it moves toward its climax.