How different are the following two sentences:
I am not allowed to sleep during the day.
I am not allowed to sleep in the day.
How different are the following two sentences:
I am not allowed to sleep during the day.
I am not allowed to sleep in the day.
Graphically "in" can be represented with a point on a section of a line, standing for a period of time.
"during" belongs to the word family duration (in German there is still the verb dauern). "during" could be represented graphically by a section of a line for time period and a second parallel line covering all of the period of time.