Downing Street is the most exclusive street in Britain, not because it only has three houses along its short【B1】______, nor part

Downing Street is the most exclusive street in Britain, not because it only has three houses along its short (26) length, nor particularly because of its location between Whitehall and St. James’s Park, but because its only residents are (27) chosen from the elected Government.
  Numbers 10 and 11 Downing Street are the (28) official London residences of the Prime Minister and the Chancellor of the Exchequer—the First and Second Lords of the Treasury. Numbers 9 and 12 are the offices of their key (29) staff and colleagues in Government.
  The location has been (30) prestigious for centuries, of course, as even before modern government the (31) site was close to Westminster Abbey and later Whitehall Palace.
  But it was Sir George Downing who made the most of its (32) potential and built the Street of houses that bears his name.
  In his later (33) career as a property speculator and developer, Downing sought--and won--the permission of King Charles II to name his prestigious new development at St. James’s Park "Downing Street".
  (34) The street’s links to the Government date back to 1732, when King George H offered Number 10 as a gift to Sir Robert Walpole.
  Walpole is now recognized as Britain’s first Prime Minister, (35) but his official title then was First Lord of the Treasury, a title every Prime Minister still holds. He declined the gift, but agreed that it become the official residence for the First Lord and subsequently moved in.
  (36) From 1828. Number 11 became the official residence of the Second Lord—the modern Chancellor of the Exchequer.