Is the sentence trees were bing blown over by wind a passive voice or an active voice?

The sentence "Trees were being blown over by wind" is in the passive voice.

Here's why:

* Passive voice: The object of the action (the trees) is the subject of the sentence. The action (being blown over) is performed by the wind, but the wind is not the subject.

* Active voice: The subject of the sentence would be the doer of the action (the wind). For example, "The wind was blowing the trees over."

Let me know if you have any other sentences you'd like to analyze!