the+姓氏的复数表示一家人,谓语动词用复数
the+上文提到的特定事物（当然可以是名词复数：I have been here for two weeks.The two weeks have been wonderful.)
the+双方都知道的事物（该事物也可以是复数名词：Shut the wondows before
you leave the lab.)
in the 1990s在20世纪90年代