I am a bit confused about these sentences below. The word "encumbered" baffles me. "Encumbered" is usually used in passive sentences. I am not able to understand the agent in these following structures. What confuses me is when the agent is not animate, that is, the object in the passive sentence followed by "by" is not a person. For instance,
1. Mike was killed by Rob. (Passive)
1.1 Rob killed Mike. (Active)
The use of "encumber" in following sentences,
1. Women tennis players are not encumbered by long, heavy skirts and high necked blouses.
2. We were encumbered by equipment and supplies.
Here, the thing that does the action is not animate. What could be the active voice sentence? Are the following constructions correct?
1.1 Long, heavy skirts and high necked blouses encumber women tennis players.
2.2 Equipment and supplies encumbered us.
I am referring to this dictionary.