必不可少

absolutely necessary / indispensable / essential

certainly / must / will / necessarily

no; not so / (bound form) not; un-

cannot / should not / must not

cannot; should not; must not

can / may / able to / to approve / to permit / to suit / (particle used for emphasis) certainly / very

used in 可汗[ke4 han2]

indispensable; essential

few / less / to lack / to be missing / to stop (doing sth) / seldom

young

absolute necessity / sine qua non