Somebody check my analysis here...
In the dialog, Galba and Marcus, the first sentence is:
Quis, Marce, est legatus cum pilo et tuba?
The answer key gives, as a translation: Who, O Marcus, is the lieutenant with the spears and trumpets?
However, "pilo" and "tuba" are presented in the ablative, singular (-o and -a), which should translate to: Who, O Marcus, is the lieutenant with the spear and trumpet?
The ablative, plural of these nouns would be "pilis" and "tubis", I believe.
Also, in the 4th sentence: In oppido Sextus cum filiabus habitat, I think filiabus suggests abl, pl again. So, my translation would be:
Sextus lives in the town with his daughters, rather than daughter, as given in the key.
Am I missing something?