I think its important that you learn that in arabic the verb to open is used in cases like this. I visit family in the middle east and in pakistan and when they speak english they say "close/open the light/faucet" not turn on. Because in their language thats the literal translation.
While I think it's important to understand the literal translation, I think there is value in accepting "I turn on the faucet" with text either way describing the colloquial/literal translation. I seem to remember seeing this feature in my Spanish lessons and gaining a better understanding because of it. From the perspective of using the reverse course (English from Arabic) it might be more helpful as well.
I agree with the learners who are asking you to accept "I turn on the faucet/tap" or "I turn the faucet/tap on" as acceptable English translations. Even though we are here to learn Arabic it's not a great use of time to have to remember a literal, incorrect translation in English to progress. Thank you for considering our request.
Hello. The problem is that فَتَحَ/يَفْتَحُ does not mean to "turn sth. on". It means "to open sth." (anything, like a door, a box, a book, the faucet). But you can't use فَتَحَ/يَفْتَحُ to say e.g. "I turn on the radio." ("to turn on" is a completely different verb). So as this course is about learning Arabic and not about learning English it makes more sense to teach the correct meaning of the Arabic word, even if often it does sound a bit weird to a native :-)