不堪设想

too horrible to contemplate / unthinkable / inconceivable

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

cannot bear / cannot stand / utterly / extremely

to endure / may / can

to set up / to arrange / to establish / to found / to display

to imagine / to assume / to envisage / tentative plan / to have consideration for

to think / to believe / to suppose / to wish / to want / to miss (feel wistful about the absence of sb or sth)

to think (about) / to think of; to devise / to think (that); to believe (that) / to desire; to want (to) / to miss (feel wistful about the absence of)