Respuesta :
Sentences
can either used as active or passive voices. A sentence is active the subject pf the sentence is the one performing the action with the formula:
subject + verb + receiver of the action. A sentence is passive when the subject
is the one upon by the verb. The formula is subject + be + verb past participle
+ receiver of the action. In the sentences above, the answer is letter B: A commencement speech has
already been written by the principal.
Answer:
B). A machine mixes the concrete with water.
Explanation: