TASK DEFINITION: Two analogies on manipulating items in a kitchen is given in the form "A : B. C : ?". The phrase "A : B" relates item A to its appropriate manipulation B. Your task is to replace the question mark (?) with the appropriate manipulation of item C, following the "A : B" relation. Your answer should be a verb which shows a way to manipulate the given object.
PROBLEM: box : open. faucet : ?

SOLUTION: turn

PROBLEM: letter : open. pump : ?

SOLUTION: pump

PROBLEM: shoe : untie. backpack : ?

SOLUTION:
unzip