The prefixes
Ad- Ante- Circum- Con- In- Inter- Ob- Post- Prae- Pro- Sub- Super-
What else do they need
They need an object, they cant stand alone
Praesum
I am at the head of….(dative)
I command the sailors
I am at the head of the sailors
Nautis praesum
Praeficio
I make at the head of…(dative)
I place in command of…(two words, -ficio:facio (trans) will govern the accusative, prae- will govern the dative
I place you in command of the sailors
Te nautis praeficio
These datives usage is basically
Referential
I make you in command (with reference to the) sailors
Many verbs compounded with prefixes govern
The dative case