useful

using or operating an item without knowledge or following given instructions

manual, handbook

a credit card

useless

useless

a chemical reaction

reaction

usability

respiratory

peacefully use

useless or hopeless (normally used to describe a person)

External force

one who is obedient and productive

noun; magical function, subtle application

Household goods

practicality

verb; commandeer; expropriation; requisition

apps

applicable skills / techniques; application technology

guessing of one's mind (spoken)

to misunderstand someone's purpose or intentions (e.g. in a romantic situation)

the daily necessities

to regret not having studied harder in the past and only realising now that you need to use that knowledge

useless

civil aviation

oxidation

(idiom) to learn the advantages of Western as good use

digestion

to be in power; to allow the swaying of one's action as a result of something (for example one's emotions '感情用事')