I'm not sure how I can decide which part is a subject and which part is a predicate.
Subject：The object that starts the statement/sentence. It usually tells us who/what to be mainly described. In Chinese, the subject is usually put at the beginning.
我是学生。(I'm a student.) “我” is a subject, because it is the MAIN object to be described.
Predicate：The action, statement of the subject. In Chinese NOT ONLY a verb can take the predicate, but adjectives and some other words can also take this position. This is the MOST DIFFERENCE between Chinese and English.
1）他很帅. (He's much handsome). 帅 is an adjective, used as a predicate to describe how he looks. In English, we must use "be" as the link verb to link an adjective with the subject.
2）他在吃饭. （He's having lunch）吃 is a verb, used as a predicate.
Sorry but you CANNOT use “的”，you should use “得”. Because if you understand the meaning (Some verbs without a complement to tell you how the predicate develops, the meaning of the statement isn't complete).
Please think about this statement again:
他住. (He lives).
Even in English, you will reguard "live" as "he has his own life". Because when you reguard "live" as “住” (locates in someplace). The statement isn't complete. We neither know where he lives nor how he lives. And so for the Chinese statement.
Now if you wanna make the statement complete, in English maybe we say：
He lives very happily. （他住得很愉快）.
Notice that happily just describes how he lives (the statement of the period when lives in someplace). And in Chinese, this is called a 补语(Complete Statement).
补语 is usually used in two senarios:
1) When a S+V, and the "V" (verb used as a predicate). The meaning isn't complete, and we should complete the sentence by attaching something to describe "How/Where……ect" the verb develops……. Such a statement is called a "Complete Phrase"（补语成分）.
Here we MUST ADD “得”, like:
Notice when a complete phrase is used to describe a verb's degree, you can add “得”. However if it is used to describe the result of a verb. We CANNOT add that. Please compare the two statements:
a) 他吃完了。 (完 is a complete phrase to describe 吃, means He has finished eating).
b) 他吃得完。 （得, if you add this, this is of "Future Time" to describe that he can and will eat up.）
2) Even if you see a whole statement (something like S+V+O), but if we think we still need to describe the degree of the predicate about (how, where……). The 补语成分 can be also attached at the end of the setence as an optional thing.
他吃饭吃得快 （他吃饭：is a whole S+V+O, complete statement. But we wanna descirbe how he eats. so “吃得快” can be also attached at the end of that）