Abbreviations for important components in a sentence.
Subject (S) Verb (V) Object (O)
Complement (C) Adverbial (A) Direct Object (DO)
Indirect Object (IO)
There are basically five sentence patterns in English Grammar. They are
e.g.
SV Subject + Verb
SVO Subject + Verb + Object
SVIODO Subject + Verb + Indirect Object + Direct Object
SVC Subject + Verb + Complement
SVOC Subject + Verb + Object + Complement