Правильно ли я обозначила времена предложений в страдательном залоге? it is well known that one form of energy can be changed into another. – present indefenite thus, the mechanical energy of falling water is turned into electric energy. – present indefenite when an object loses its potential energy, that energy is turned into kinetic energy. – present indefenite we have already seen that energy of some kind must be employed to generate the electric current. - present perfect these needs will continue to grow as more motors and melted metals are used in industry and more electric current is employed in everyday life. - future indefenite
4главное предложение в perfect,a вот must be employed тоже present indefinite passive.
5гл.предложение -future ind.,а are used тоже present indefinite passive.
is imployed тоже pr.ind.