影

1. Origins, structure, and basic meaning

• Structure: 影 is read as かげ and is a noun for a cast shadow or a dark human outline.
• Basic usage: 木の影 refers to the tree's shadow, while 人の影 can refer to the shadowy form of a person.

2. Common pitfalls and similar expressions

• Cause of the shadow
  • The で in 夕日で presents the setting sun as the reason the shadow grows long.
• Path of movement
  • In 窓の外を横切る, を marks the space across which the shadow passes.