some changes have taken place in people’s diet in the past five years．the major reasons for these changes are not far to seek．nowadays，more and more people are switching from grain to meat for protein，and from fruit and vegetable to milk for vitamins．

　　7．表示事实、现状

　　1）we cannot ignore the fact that．．．

　　2）no one can deny the fact that．．．

　　3）there is no denying the fact that．．．

　　4）this is a phenomenon that many people are interested in．

　　5）however，that’s not the case．

　　例如：

　　we cannot ignore the fact that industrialization brings with it the problems of pollution．to solve these problems， we can start by educating the public about the hazards of pollution．the government on its part should also design stricter laws to promote a cleaner environment．

8．表示比较

　　1）compared with a，b．．．

　　2）i prefer to read rather than watch tv．

　　3）there is a striking contrast between them．

　　例如：

　　compared with cars，bicycles have several advantages besides being affordable．firstly，they do not consume natural resources of petroleum．secondly，they do not cause the pollution problem．last but not least，they contribute to people’s health by giving them due physical exercise．

　9．表示数量
 

　　1）it has increased（decreased）from．．．to．．．

　　2）the population in this city has now increased （decreased）to 800，000．

　　3）the output of july in this factory increased by 15％ compared with that of january．