Translation:There is a shoe sale at the store.
I thought there should be "Aia" at the start of the sentence, meaning location of the shoe sale is at the store. I think of "aia" meaning "there is." The sentence starting with "he" means to me just "a shoe sale at the store." Where are the words "there is " in the sentence?
I already ranted about this on another lesson because DL should not be teaching this as a complete sentence. As Barbara just stated (well, 9 month ago), it just means "A shoe sale at the store," which at least DL now accepts as a possible answer (I just tried it because that's what it means to me). You COULD use Aia as long as you use "KEKAHI kūʻaiemi kāmaʻa" for "a shoe sale": Aia kekahi kūʻaiemi kāmaʻa ma ka hale kūʻai.
If you ever just said "he kūʻaiemi ma ka hale kūʻai" to anyone, they would most likely keep looking at you waiting for you to say something about it.
Kala mai. I already ranted elsewhere. This is just the short version. :-)
This is a locational sentence and Barbara is correct that it should begin with Aia. He can follow aia in these sentences as in "Aia He Kaheke" the Hawaiian/English book and in "Ka Lei Ha'aheo" ha'awina 'eiwa page page 75. This is one of the patterns where he can be used within a sentence. Evidently Duolingo is using a sentence structure known as a Pepeke He'o which is used at the beginning of sentence for the use of English "there" as in "there is" or "there are" that are different from the "there " referring to a place. The meaning conveyed with Pepeke He'o beginning with "he" can be indicated with "Aia he" as shown in the following sentences 1. He lipine ma ko'u lei / Aia he lipine ma ko'u lei. 2.He mau kaula ma ke pakaukau/ Aia he mau kaula ma ke pakaukau. 3.'Elua hoaaloha me a'u/ Aia 'elua hoaaloha me a'u. This is the reason that Duolingo is using this sentence structure. It's interesting that " a shoe sale is at the store" is a correct answer! This information can be found on page 174 of "Na Kai 'Ewalu" volume 1.