5.110 'by' for specific time

'By' is used to emphasize that an event occurs at some time before a specific time, but not later. 'By' is also used to indicate that a process is completed or reaches a particular stage not later than a specific time.

• By eleven o'clock, Brody was back in his office.
• The theory was that by Monday their tempers would have cooled.
• By 1985 there will be 5,000 robots on the job.
• Do you think we'll get to the top of this canyon by tomorrow?
• By now the moon was up.
• But by then he was bored with the project.