茫然失措

at a loss (idiom)

vast, with no clear boundary / fig. hazy / indistinct / unclear / confused

blankly / vacantly / at a loss

correct / right / so / thus / like this / -ly

to lose / to miss / to fail

to be at a loss

to handle / to manage / to put in order / to arrange / to administer / to execute / to take action on / to plan