a certain problem

[elduce]

In the back of book exercises Ch. 34, #25:

Ea nocte profectus, Caesar ad quandam insulam clarissimam venit.

I was confused by the use of quandam, and the glossary had no answer. Then I understood: quandam was really quamdam with the 'm' becoming an 'n', just like eamdem becomes eandem. Wheelock did not mention this (maybe he wanted the reader to figure it out).

Vale

[benissimus]

In the back of book exercises Ch. 34, #25:

Ea nocte profectus, Caesar ad quandam insulam clarissimam venit.

I was confused by the use of quandam, and the glossary had no answer. Then I understood: quandam was really quamdam with the 'm' becoming an 'n', just like eamdem becomes eandem. Wheelock did not mention this (maybe he wanted the reader to figure it out).

Vale

It looks like you have answered your own question. The M of an accusative singular or genitive plural ending will change to N before the suffixes -dam (used with the relative pronoun) and -dem (used with the demonstrative pronoun).