I visited my aunt in Kyoto during the summer vacation.
During indicates a period or range of time (having duration) and is used to say that something happened. “throughout this time” or “sometime within this time”. A clause with during focuses more on what happened—the activity, event or experience.
|ACTIVITY THROUGHOUT THIS PERIOD|
|We sat on the beach during the morning hours.|
|The beach is fulll during Easter.|
|We went to the sea often during our childhood.|
We spent time near the sea during our stay in Greece.
In specifies when an activity occurs/occurred, the timing of the activity—part of day, month, season, year. A clause wit in focuses more on when something happened than what happened. In may specify how soon or how long something takes/took. (See timelines in the next section.)
|We sat on the beach in the morning.|
|DURATION—QUANTITY HOW LONG?|
|We swam a mile in an hour. (within an hour’s time, 60 minutes)|