kěn
to gnaw
to nibble
to bite
kěn shū
lit. to gnaw a book
to study
to cram
kěn lǎo
(coll.) to live with and depend on one's parents even upon reaching adulthood
kěn lǎo zú
(coll.) adults still living with and depending on their parents
zuǐ kěn ní
to fall flat on one's face