Roman Catholics across the city turned to cheat sheets to make it through Mass yesterday.

The extra help was needed as the most extensive, liturgical-language overhaul since Vatican II went into effect, leaving many parishioners fumbling to replace the words they’ve spoken for decades.

Cathedral Basilica of St. James in Brooklyn was one of several parishes that handed out large cards to worshipers with new responses in bold.

But there was stumbling from the start — when Monsignor John Strynkowski greeted churchgoers with “The Lord be with you” and more than half responded with the old “And also with you,” instead of “And with your spirit.”