one must accept
one must accept at invitation, Pl. Ep. 328b, Plu. QConv. 2.709d.
II one must answer
one must answer, τι περί τινος Pl. Sph. 261d.
2 one must understand something left out
one must understand something left out, Phld. Rh. 1.115 S., Mort. 30, Sch. Pi. O. 10.84, 11.19, etc.; ὅτι . . Plu. Aud.poet. 2.34b.