6、如: This isapenand that isapencil. Wearebusy these days. In those daystheworkershadahardtime.2. 有时that和those指前面讲到过的事物,this 和these则是指下面将要讲到的事物,例如: Ihadacold. That'swhyIdidn'tcome. WhatIwanttosayis this ;pronunciationisveryimportantinlearningEnglish.3. 有时为了避免重复提到的名词,常可用tha