L2 writing 8 (short/long vowels)

Yesterday and today we worked on short/long vowel pairs, starting with a:

wann / Wahn
kann / Kahn
Mann / mahnen
Bann / Bahn
sann / Sahne
Lamm / lahm
an / ahnen
     / Hahn
     / Zahn
     / nahm

Yesterday I drew up the list above, explained the double n/m as marker of the short (except with an) and -h- as marker of the long vowel, then had J pronouce as I pointed to the individual words. This morning we did a dictation: 

He got all of them right!