Questions & Answers about Czy twoja siostra jest studentką?
Why does the word for student end with -ą instead of -a here?
This is the Instrumental case! When you use the verb być (to be) to talk about someone's profession, nationality, or role, the noun changes its ending. Since studentka is a feminine noun, the ending changes from -a to -ą.
Why do we use twoja instead of twój?
Possessive words like "your" have to match the gender of the noun they describe. Because siostra (sister) is a feminine noun, we must use the feminine form twoja. If you were asking about a brother, you would use the masculine form: twój brat.
How does Czy work in this question?
Czy is a word used to start "yes or no" questions in Polish. In English, we change the word order to make a question ("Is your sister..."), but in Polish, you can just take a regular sentence (twoja siostra jest studentką) and put Czy at the very beginning to turn it into a question.
Where is the word for "a" in "a student"?
Polish does not use articles like "a", "an", or "the". The single word studentką translates to "a student" all by itself.