I had much trouble with this fragment:
"Varro" speaking:
(cut and pasted from here: http://www.thelatinlibrary.com/cicero/acad.shtml)nostra tu physica nosti; quae cum contineantur ex effectione et ex materia ea quam fingit et format effectio, adhibenda etiam geometria est. . . .
Translation ("Varro" speaking):
You know about our theories of nature [nostra . . . physica]. They ought to be framed by [the principle of] efficient cause and by the matter that efficient cause molds and shapes. They [the theories of nature] should also have applied to them [the discipline of] mathematics [geometria].
readings:
physica: neuter plural, accusative
quae: relative pronoun, mominative, neuter, plural, agrees with physica in gender and number
contineantur: the subject is quae. The subjunctive here expresses intention.
adhibenda: agrees with physica, future passive participle
effectio: efficient cause