A circuit with two independent and two dependent sources is solved by the superposition method. Independent sources are turned off one at a time and the contribution of the on source is calculated. Dependent sources should not be turned off.
A circuit with two voltage sources and two current sources is solved by the superposition method. The contribution of each source is calculated individually and the response is found by adding the contributions.
Turning off a source used in solving circuits with the superposition, means setting its value equal to zero. A voltage sources become a short circuit when turned off. To turn off a current source it should be replaced by an open circuit. Dependent sources cannot be turned off.