Why is this Rule 90 of Evidence Act so bloody hard to grasp?

Maine toh har course mein se Evidence Act ka chapter padha hai par agar aapko pata nahin hai ki Rule 90 kya hota hai toh bhai aapko kabhi kabhi confuse ho jayega. Ab 3 din hain exam ke aur main yehi soch raha hoon ki Rule 90 ki wajah se kya hoga? Ye hai ki, agar koi statement hamaare presence mein di gayi hai jo humein galti ki baat karega, tab hum use reject karenge ya phir iska adhikar rakhenge. Ismein yeh bhi aata hai ki agar use reject karna hai toh yeh statement humesha present hameshaa reject karo ya phir hum present hameshaa reject karo...