TASK DEFINITION: In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.
PROBLEM: A chancellor is a leader of a university or a college .

SOLUTION: A chancellor is a leader of a college or university , usually either the executive or ceremonial head of the university or of a university campus within a university system .

PROBLEM: Masonry is the building of structures from individual units laid in and bound together by mortar .

SOLUTION: Masonry is the building of structures from individual units , which are often laid in and bound together by mortar ; the term " masonry " can also refer to the units themselves .

PROBLEM: The Boeing 737 is a jet airliner .

SOLUTION:
The Boeing 737 is an American short- to medium-range twinjet narrow-body airliner developed and manufactured by Boeing Commercial Airplanes .