Question: Isn't it that once Asr prayer time has begun you can't pray other salaah?
Answer: No, You may pray as much as you like before you pray the Asr prayer itself. However, Asr should not postponed to the time during which the sun becomes easy to look at (the Makruuh time)- during that time only Asr can be prayed validly, and it is makruuh to postpone Asr to that time. Even after Asr you may pray make up prayers, but not nafl prayers, as long as the makruuh time has not entered.
