The sentence is not a proper question. It is supposed to be a statement. The question mark is only there to emphasize the disbelief of the speaker regarding the high prize. To make it so that it would be a real question (Was, kostet der Stift 70 €?) sounds more like what you would say when you couldn't hear what the prize was when you asked the first time. This you would say if you weren't sure of the prize itself, not if you wanted to point out that 70€ for a pen is ridiculous.
The structure: Was, [statement]? Can be used in nearly every context.
What is the point of this sentence? Why the exclamation at the beginning? There is not enough expression of incredulity in the speaker's voice to cue the learner in. 'Did the pen really cost seventy euros' would be better.
People are absolutely losing their minds over this sentence for no reason. The only thing wrong about any of it is the intonation of the German speech bot. I was confused because there's no pause between "Was" and the rest of the sentence, but other than that, both are grammatically correct in writing. It's really not that complicated. "Was" is doing the same here in both languages, expressing surprise or incredulity.
Yes, it makes no sense without the comma. And when the sentence makes no sense and you try to add a word to turn it into a sentence, it marks it wrong and says that the answer is "What the pen costs 70 Euros."
There's no comma when choosing words, the word choices don't make a valid sentence that's acceptable, and the stated answer makes no sense.
This would be an acceptable explanation if the speaker were to put some incredulity into her voice.
Absent the punctuation, the "English" translation is not an English sentence. This one was inappropriate for this form of answer. A student learns already that they cannot merely expect German punctuation to transfer directly into English punctuation, and so the concept is extraneous to the immediate lesson without first introducing the departure from the established pattern of lessons -- or at least departing from the answering method to offer a comma, and thereby hint that this answer may require one. I made a grammatically correct sentence from the limited options available, even though I felt my answer to be only a guess, because I was not given the option to form a better answer that would still be grammatically correct. The inclusion of the required comma in the correction, which was not offered with this answering method feels like a betrayal of my trust in Duolingo (particularly after the app has been regularly refusing credit for many completed lessons, and the lack of response to my bug report of the same).
I REALLY wish Duo would put a "comma" (,) box for us to click on, as it is totally incorrect to not have commas in certain places, as it changes the meaning in both English and German. There HAS to be a comma in this sentence, for example, in order for it to make sense, but we cannot select it when answering, because there is no "box!"
I agree, but it's also not clear why the "what" is used. In English, it would have the same meaning without it. The "What?" could also be a different sentence. On the other hand, turning a sentence into a question by using a question mark doesn't work in all languages or have the same effect, especially without the "what."
Can I simply say "Der Stift kostet siebzig Euro?" as opposed to moving the verb as usual, and if so, what's the connotation?
In French, for example, it's an ordinary option for forming a question. In English, it would add an element of surprise. In German, that wasn't explained.
That is a different meaning of Stift, which is as a home for orphans, nuns, etc. For "pen" Stift is masculine. (A few words have different gender depending on meaning, e.g., Leiter)