Ch.13: EIUS vs. SUUS
Remember that forms of the adjective "suus,sua,suum" refer to the SUBJECT'S OWN thing; "eius" is the genitive of possession for the 3rd pers. pronoun
Step 1: Read the sentence and ask yourself, "Is the his/her/its/their" referring back to the SUBJECT of the sentence?
If the answer is NO, go to path 1
If the answer is YES, go to path 2
Path 1: it's either eius, eorum, or earum.
Path 1a: Is it singular? If yes, use eius.
Path 1b: Is it plural? If yes, use eorum or earum, depending on whether it's referring to masculine plural or feminine plural noun.
Path 2: Use the suus,sua,suum chart.
Path 2a: What gender is the word his/her/its/their modifies?
Path 2b: What gender and # is the word his/her/its/their modifies?
Path 2c: What gender, #, and case is word his/her/its/their modifies?