suī rán / tā men / xìng shì / bù tóng / dàn / gǎn qíng / shēn hòu / bǐ cǐ / shì tóng shǒu zú

虽然他们姓氏不同，但感情深厚，彼此视同手足。

Although they have different surnames, they have deep feelings and regard each other as brothers.