"What was in this bottle?"

Translation: Co bylo v této láhvi?

[linguistenator]

Can "Co bylo v této flašce" be added?

[Jamie08MD]

The word "flaška" is Common Czech, non-standard.

[simeki]

Co bylo v tyto láhvi? - could it be "tyto"?

[RoryBaskin]

Tohle is nominative and této is locative? Thanks in advance! And if anybody has any information as to when we may get notes on the locative to accompany this page, they would be greatly appreciated!

[VladaFu]

We have the feminine gender of tento here. Tato is nominative, této is locative. You can check the declension table of tento and tenhle at wiktionary.