Hi Casiopea,
Thanks for the reply. This is a very interesting thread. I now see the advantage to having parallel constructions in some situations. At the same time, I'm still struggling with a few of your points. I'm relatively new to this whole English teaching deal, so please bear with me.
1. By your example:
The eggs must be broken <passive>
to make an omelet <active>
What makes the adverbial phrase active? I see no agent. Is it simply that the verb precedes the object?
I can see how it can be changed to passive,
so that an omelet [is/can be] made
because passive voice doesn't require an agent in some circumstances. I always thought active voice needed an agent. Can you please clarify?
2. Speaking of the agentless passive, are there any instances in which the use of non-parallel constructions is preferred or even required?
For example:
Native Americans were systematically displaced <passive>
to make room for white settlers. <active>
This sentence seems perfectly fine to me, even though the constructions are not parallel. It gives me no pause. If I change the the main clause to active,
The US government systematically displaced Native Americans...
I shift focus away from the patient (Native Americans) and introduce an agent that may be redundant (obvious from context or assumed to be known, for example). Assuming that I like to keep the main clause passive, what are my options if I want to maintain parallel structure? Check out:
so that room could be made for white settlers - passive, but clumsy
so that room for white settlers could be made - same
so that white settlers could have room made for them - ?ugh. I don't even think this one is parallel
so that white settlers could be accommodated - Aha! This one is passive and elegant. It looks like a winner.
But is it really that much better than the original? It rewords the phrase in a way that shifts focus toward "white settlers" and away from the action "to make room", which I'm not sure I want to do.
What do you think?
Am I just splitting hairs?
The thing is, lately my students have been stumping me with questions I'm not able to answer, so I appreciate anyone's input.
Cheers