guilingchang wrote:I'm learning patristic Latin, and I want a systemic grammar book of that, anyone who can recommend one? Thank you!
I have been unable to identify a grammar directed specifically to patristic Latin. I therefore suggest you use "A Primer of Ecclesiastical Latin" by John E Collins, which is very thorough and states in its preface that "the ecclesiastical Latin of this text is largely that of Jerome and Ambrose".
I have also become aware of a Latin reader in patristic authors which includes grammar/syntax notes but which appears to be available only second-hand, namely "The Osterley Selection from the Latin Fathers" by Joseph Crehan.