    Sentence: ‘1: Senator. Hill appeared  ‘completely unaware of the issue, which  has. been .of serious. concern to.US ,  Australian : and.. ‘British. “intelligence’  officers. . . .    Sentence 2: But Senator Hill appeared  unaware: of thé, intelligence ‘problems  that have been of serious concern.to'US   ‘Australian’... and’: . British. military  intelligence officers .    