Your answer is the wrong way round: it means that the crows would train the humans. I agree that "can" seems too strong, given the wording of the last sentence in the original text. ", so blame the question-setter!
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
samuraigirlI've corrected it this way:By being trained like dogs or dolphins to follow what humans direct.Now, is it an answer to this question?If you want a "By ..." answer, I think "By keeping our cities clean and helping to save people in emergencies" more specifically reflects what the text says.
samuraigirl>By the w
samuraigirlBy the way, how about this answer:"How can crows help humans?""They can be trained like dogs or dolphins to help humans."I find this less satisfactory. To me, the "How?" question seems to expect an answer that refers to keeping cities clean and saving people in emergencies.