Translation:After two days without water, the horse was very sick.
There is only one clause in Czech and although my knowledge of the English grammar terminology is limited, I would not call the fronted adverbial a separate clause.
The adverbial however, is the origin of the declaration (the topic, východisko výpovědi) and to not change what the sentence stresses and what it brings as the new information you should keep the adverbial fronted in English.
Your proposal is really too English-like. Czech does not front adverbials like English does. The adverbial phrases are always an integral part of the sentence. It just sounds wrong in this case with "byl (nemocný)" and it does work with some other longer verbs in the present or future tense. It is really about the stress and intonations patterns (melody) of the sentence. It just sounds wrong this way even though the verb is not a clitic and it will sound wrong with some similar ones too.
Can't “nemocný” also be translated as “weak”? That's what it more or less translates to literally, in the end. And I think that it could also be considered a consequence of not drinking water for two days.
My answer was: »After two days without water the horse was very weak. After two days without water the horse was very weak.« in a CZ to EN exercise.
I reported it.
"bezmocný" is "powerless" (also literally), it still has a different meaning than "weak" (slabý, chabý). You can be really strong but when you're tied up properly, you're powerless anyway, or the same if you're unable to do anything about your situation despite all your strength.
"nemocný" developed from "not having (enough) power/strength" centuries ago, but now it just means "ill" and native speakers don't normally perceive the etymology anymore. - i.e., the opposite of "nemocný" is "zdravý", not "mocný" (which means "powerful" or "mighty").
Thanks a lot, this makes sense to me by now. So, would “not having (enough) power/strength” be translated as “bezmocný” as well, so that it became an umbrella term for such conditions? If people do not perceive the etymology anymore so that “nemocný” was replaced in meaning, I think that the original meaning had to be expressed otherwise.
However, thanks a lot for the clear explanation!
Yes, “not having (enough) power/strength” is bezmocný, that is the main meaning of that word. But mainly when ruling. Or when you can't do anything with the situation. Not when you are very weak physically.
If you are very weak, you are slabý - both physically and as a ruler.