昨日

1. Origins, structure, and basic meaning

• Structure: 昨日 is read as きのう and means yesterday.
• Basic usage: It can locate an event one day before today or modify something borrowed on that day.

2. Common pitfalls and similar expressions

• Meeting a friend yesterday
  • 昨日: I met a friend at the library yesterday. Example: 昨日、図書館で友人に会いました。
• Referring to something borrowed yesterday
  • 昨日: Today I will return the umbrella I borrowed yesterday. Example: 昨日借りた傘を今日返します。