一脸茫然

puzzled / bewildered

one / single / a (article) / as soon as / entire; whole; all; throughout / "one" radical in Chinese characters (Kangxi radical 1) / also pr. [yao1] for greater clarity when spelling out numbers digit by digit

face / CL:張|张[zhang1],個|个[ge4]

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

blankly / vacantly / at a loss

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