My sister is ten years old and my brother is eleven.(改为同义句）

   My sister is . .my brother.
   2.The population of Shanghai is 13 million.(改为同义句）

   Shanghai . . . .13 million.
   3.The buildings in New York are taller than the buildings in Washington,D.C.(用一个词替换than后面的'the bulidings'
  The buildings iin New York are taller than .in washingtong,D.C.