Imperium et actus imperatus sunt unus actus humanus (sicut quoddam totum est unum, sed est secundum partes multa), quia actus imperatus non est nisi propter imperium.
Command and the commanded act are one human act (just as a whole is one, yet in its parts, many), because there is no commanded act unless according to the command.
Si essent potentiae diversae ad invicem non ordinatae, actus earum essent simpliciter diversi. Sed quando una potentia est movens alteram, tunc actus earum sunt quodammodo unus; nam "idem est actus moventis et moti", ut dicitur in III Physic.
If the distinct powers are not ordained to one another, their acts are diverse simply. But when one power is the mover of the other, then their acts are, in a way, one; since "the act of the mover and the act of the thing moved are one act" (Phys. iii, 3).
In actibus humanis, actus inferioris potentiae materialiter se habet ad actum superioris, inquantum inferior potentia agit in virtute superioris moventis ipsam.
In human acts, the act of a lower power is in the position of matter in regard to the act of a higher power, insofar as the lower power acts in virtue of the higher power moving it.
Ens autem simpliciter est substantia, sed ens secundum quid est accidens (vel etiam ens rationis).
A substance is a being simply, whereas an accident (or even aspectual being) is a being only in a certain respect.
Esse unum genere vel specie, est esse unum secundum rationem.
To be one in genus or species is to be one according to the consideration of the aspect.