By

자료: Collins Cobuild, 

13. PREP: 

If something happens by a particular time, it happens at or before that time.

• By eight o'clock he had arrived at my hotel.
• We all knew by then that the affair was practically over.

14. PREP: 

If you do something by day, you do it during the day. If you do it by night, you do it during the night.

• By day a woman could safely walk the streets, but at night the pavements became dangerous.    
• She had no wish to hurry alone through the streets of London by night.