Tā de shēngmǔ zài tā hěn xiǎo de shíhou jiù qùshì le.
Her birth mother passed away when she was very young.
Tips
usage
生母 specifically means biological mother, as opposed to 养母 (yǎngmǔ, adoptive mother) or 继母 (jìmǔ, stepmother). 生父 (shēngfù) is the corresponding term for birth father.
