空空如也

as empty as anything (idiom); completely bereft / to have nothing / vacuous / hollow / empty (argument, head etc)

empty / air / sky / in vain

to empty / vacant / unoccupied / space / leisure / free time

empty / vacuous / nothing / vacant / in vain / all for nothing / air-to-air (missile)

as / as if / such as

(adverb) also; both ... and ... (before predicates only) / (literary) particle having functions similar to 啊[a5]