请看我的程序:
unit Ucom2;interface
uses
Windows, Messages,Dialogs;
type
ICanFly=interface
  ['{F8BEAD0A-98F0-426F-B96A-FABBA6C4FA07}']
  function Fly:string; 
end;end;implementationend.
然后在单元Ucom1用到:
type
  TAirplane=class(TInterfacedObject,ICanFly)
错误提示:
[Error] Ucom1.pas(21): Undeclared identifier: 'Fly'
请问错在那儿?