Complex sentence: The pigeon, carrying the data on a memory stick, arrived in one hour eight minutes, with the data taking another hour to upload: during the same two-hour period, only about 4% of the data had been transferred over the ADSL link.
Split into simpler sentences: The pigeon, carrying the data on a memory stick, arrived in one hour eight minutes, with the data taking another hour to upload. During the same two-hour period, only about 4% of the data had been transferred over the ADSL link.