3、t为...而担忧21.dependon=relyon依赖;取决于二.重点句型1.Whataboutdoingsth?例:Whataboutlisteningtotapes?2.by的用法a.介词 prep. (指交通等)乘;例:The man came by bus. 那人是坐公共汽车来的。They went to Shanghai by plane. 他们坐飞机去上海。b.表示做某事的方式、方法结构:by+V-ingIstudybymakingwordcards.3.现在完成时态结构:havedone例:Haveyo