At, on, in: choose scale and boundary, not a Vietnamese translation

📍 Why “at 7”, “on Monday” and “in August”?

English often treats at as a point, on as a day or surface and in as a containing period or area. These are organizing metaphors, not word-for-word translations.

Core patterns

• Time: at noon, on 12 May, in 2026.
• Place: at the entrance, on the wall, in the room.
• Fixed expressions can override the broad pattern: at night, on time, in the morning.

⚠️ Location depends on viewpoint

At school focuses on the institution or activity; in the school emphasizes being inside its building. Both can be correct in different contexts.

🔎 Draw the scene

Mark whether the speaker presents the location or time as a point, a surface/day, or a container/longer period, then check conventional exceptions.