to call into question; to challenge (the truth or validity of)

(physics) mass; quality (i.e. degree of excellence); quality and quantity

to question; to ask questions; to inquire; to bring to account; to interrogate

to question; to enquire; interrogatory

proton (positively charged nuclear particle); a prince sent to be held as a hostage in a neighbouring state in ancient China

hostage

matter; substance; material; materialistic; CL:個|个[ge4]

essence; nature; innate character; intrinsic quality

character; intrinsic quality (of a person); quality (of a product or service, or as in "quality of life", "air quality" etc)

nature; characteristic; CL:個|个[ge4]