1. Usage of "open":

"On" is a preposition indicating position, direction or time. Usually used to indicate that something or someone is on a plane, surface, line or at a specific time.

The specific usage is as follows:

Represents a surface or plane:

The book is on the desk. The book is on the table. )

There is a cat on the roof. There is a cat on the roof. )

Represents a date and a specific time:

My birthday is1October 10. My birthday is1October 10. )

The meeting is held on Monday. The meeting is on Monday. )

Refers to public transport:

She goes to work by bus. She goes to work by bus. )

2. Usage of "zai":

"In" is usually used to indicate a wider range of places, regions, countries, cities, months, seasons and so on. The specific usage is as follows:

On behalf of a larger region, country and city:

She lives in new york City. She lives in new york City. )

Thailand has beautiful beaches. )

Represents the month and season:

My birthday is in March. My birthday is in March. )

It's always hot in summer. It's always hot in summer. )

Represents a specific position inside:

The key is in the drawer. The key is in the drawer. )

I am in the library. )

3. Summary of differences:

"On" emphasizes a surface, a plane or a specific time point, and is usually used in smaller areas, dates and public transportation.

"In" emphasizes the interior of a larger area, a specific month, a season or a specific place, and is usually used in a larger area, a country, a city, a month and a season.

It should be noted that the use of prepositions is usually influenced by context, so in a specific context, choosing the right preposition can ensure accurate and clear expression.