。
She couldn't open the bottle.
Literal
She [topic-は] bottle [object-を] open [can-ことができる] was-not-able.
あける written without kanji is ambiguous between 開ける ('to open') and 空ける ('to empty, vacate, make a hole'); context picks the meaning, and in pairing with びん the reading is firmly 'open.' Many writers default to kana for these everyday verbs to sidestep the choice, though the same writer may switch to kanji elsewhere depending on tone. びん ('bottle') is most commonly written 瓶 in kanji, but the kana spelling is widespread too — Japanese tolerates a great deal of script-mixing for common nouns.