Definition: Given a text, write a compressed version of it in a single sentence.
Input: At that same time, American 11 had its last routine communication with the ground when it acknowledged navigational instructions from the FAA's air traffic control (ATC) center in Boston. Sixteen seconds after that transmission, ATC instructed the aircraft's pilots to climb to 35,000 feet.
Output:
American 11 had its last communication with the ground. sixteen seconds after that transmission, ATC instructed the aircraft's pilots to climb to 35,000 feet.