Rule reminder
'Affinché' = so that / in order that (formal, always + subjunctive, always different subjects). 'Perché' as purpose = so that (+ subjunctive, when subjects differ). If subjects are the same, use 'per + infinitive' instead. 'In modo che' = so that / in such a way that (+ subjunctive).
Ti spiego la grammatica ___ tu possa capire meglio.