If the subject in a sentence is the sender of the action, the sentence is the main dynamic. For example, I have given a briefing. I wrote this letter. Writing this action is made by subject I, which is subjective and dynamic.

On the contrary, if the subject of the sentence is the receptor of the action. At this time, the sentence is dynamic. For example, the shortest. I wrote this letter. The meaning of this sentence is basically the same as the previous one. But the subject of this sentence is not me, but faith. Writing is still sent by me, but the subject has become the recipient of the action of "writing". Moreover, passive sentences all contain the auxiliary verb werden and the second participle of the verb.