大姐 (dà jiě) means “big sister; elder sister; older sister (also polite term of address for a girl or woman slightly older than the speaker)”. It is an HSK 4 Chinese word in the HSK 3.0 vocabulary.
大姐很照顾我们。
Dàjiě hěn zhàogù wǒmen.
Big sister takes good care of us.
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