Implementation of an SO2 control technology at a plant involves several activities contingent upon each other.
Several activities are needed to entirely implement SO2 control technology.
SO2 control technology requires just one activity to successfully implement.
Neither and both are both choices.
The man is outside.
People are throwing pies at children.
She is playing with her doll.
Two swans are wet.
Public hearings would be disasterous for tax payers.