Complex sentence: It is difficult to trace accurately the various channels through which it flowed, but the probability is that it flowed past Rampur Boalia, through Chalan Beel, the Dhaleshwari and Buriganga rivers, past Dhaka into the Meghna estuary.
Split into simpler sentences: It is difficult to trace accurately the various channels through which it has flowed. The probability is that it flowed past Rampur Boalia, through Chalan Beel, the Dhaleshwari and Buriganga rivers, past Dhaka into the Meghna estuary.