Translation:While searching for a virus, she designed a new treatment.
"conceived a new treatment" should be accepted.
This section seems to translate "en" into "while", "by" and "in" at random, whereas all three would be considered acceptable English by native English speakers in almost every exercise in this section. Making us guess which of the three prepositions won the DL lottery for each of this section's many questions is a major turn-off.
The French gérondif has 3 main meanings:
- SIMULTANEITY: Je téléphone en mangeant
- CAUSE: Il a réussi en travaillant beaucoup
- CONDITION: En cherchant, tu trouveras la solution
Each of the above gerunds could be replaced with a subordinate clause with a more precise conjunction:
- Je téléphone en mangeant = Je téléphone pendant que je mange
- Il a réussi en travaillant beaucoup = Il a réussi parce qu'il a beaucoup travaillé
- En cherchant, tu trouveras la solution = Si tu cherches, tu trouveras la solution
As a consequence, the Best English translations will have to mirror these meanings and alternative constructions, and you'll have to analyse the link between the 2 events then pick which English word best fits the most probable meaning of the French sentence: while/whilst, by or in.
I believe the temporal "while/whilst" is the easiest and probably obvious in this very sentence.
Her finding happened while/whilst she was looking for something else.
So, sorry I think you've explained this and it's just not clear to me. How do you know which is which in the first three sentences? How do I know that it's "I telephone while I am eating" and not "I telephone because I am eating". Do I just parse it out because it doesn't make sense?