let the door be shut
By whom was the door opened?
This sentence is a command, it has no subject and it cannot be changed to a passive sentence.
The door was being knocked at by some body.
"Will you marry me" can be changed to passive voice as "Will I be married by you." In the passive voice sentence, the subject of the active voice becomes the object of the passive voice, and the object of the active voice becomes the subject of the passive voice.
Yes, "is addressed" is in the passive voice.
To change a sentence into passive the sentence must be active. 'Shut the door please' is not an active sentence, it is an imperative sentence, it has no subject. You could write something like this - You are asked to shut the door - but this is a bit awkward.
"They were surprised by a knock at the door." is passive voice.
By whom was the door opened?
This sentence is a command, it has no subject and it cannot be changed to a passive sentence.
The active voice sentence "Who is knocking at the door?" can be changed to passive voice as "By whom is the door being knocked?" In the passive voice sentence, the subject of the active voice sentence ("who") becomes the object of the preposition "by," and the verb "knocking" is changed to "being knocked," with the helping verb "is" moved to the appropriate position.
This
The door was being knocked at by some body.
The passive voice of ''what do you do'' is "what is done by you?"
"Your name is not known by me." is passive voice.
Passive voice
"Will you marry me" can be changed to passive voice as "Will I be married by you." In the passive voice sentence, the subject of the active voice becomes the object of the passive voice, and the object of the active voice becomes the subject of the passive voice.
Yes, "is addressed" is in the passive voice.