A relative clause can be ‘subject + verb + object’. The object in this case must be an indirect object and the noun/noun phrase being modified by the relative clause is the direct object.
nǐ kàn，zhè shì wǒ nán péng yǒu sòng wǒ de shēng rì lǐ wù 。
Look! This is the birthday gift (that) my boyfriend gave me.
wǒ bǎ tā gào sù wǒ de mì mì dōu xiě zài rì jì lǐ le 。
I wrote all the secrets he told me in my diary.
 Yip, P. C., Rimmington, D., Xiaoming, Z., & Henson, R. (2009). Basic Chinese: a grammar and workbook. Taylor & Francis.