When do you carry your backpack?
What kind of book do you like to read?
Do you buy books or do you borrow them from a library?
and (lower case) we need
program. ("programs" is not wrong)
in which (optional, but more clear) you drive
Shoes are something. ("things" is not wrong, but "something" sounds better to me. "Shoes" is an odd term, sort of a singular plural, as in "a pair of shoes")
you use both for playing games and working