The Elusive Concept of "Accrued Revenue" in Taxation

Doston, koi bataao tax law ke liye, kaise hua kya "Accrued Revenue" ka concept? Sab jante hain ki ye revenue ka tax payment ke liye kaaran hota hai, lekin textbook mein toh ek-dimaaag ki baat hui hai hi nahi. Pehle to ye hua, ki kuch aise cases hain jahaan income tax refund paya jata hai, par wo refund bhi accrued revenue ke under hi gine jaata hai. To aisa kaise hota hai? Koi aisa example batao jo CLAT PG yaa AILET PG ke liye relevant ho.