This is of great significance里面的of的作用

of介词短语在句中作表语,of的含义有六种,现分述如下：[解题过程]一、“be of+抽象名词”,这时的of短语相当于这个名词的同根形容词,作为表语表示主语的性质或特征。of的意思是“具有、具备”等,常用于该结构的名词常见的有of use=useful；of nouse=useless；of importance=important等。如：The matter is of great importance。=The matter is very important。在形容词前常用very来修饰,在“of+抽象名词”结构中,名词前常用great,much等来修饰。再如：It is o fgreat importance for college students to master a foreign language。=Itisveryimportant。。。对大学生来说,掌握一门外语是很重要的。二、“be of+集合名词或其它类型的名词”,相当于belong to或have。of表示归属关系或“有”的意思。如：The army and the people are of one family。=The army and the people belong to one family。军民是一家。三、“be of+物质名词”表示主语是“用某种材料构成或制作的”,相当于be made of或be built of。如：Our building was of bricks。=Our building was built of bricks。我们的楼房是砖建的。四、be of+(表示种类、颜色、年龄、形状、价格等）名词,多用来表示主语的特征。这类结构的主语可以是人,也可以是物,其中的of可以省略。常用于该结构的名词有：kind,age,colour,size,height,shape,type,way,price等。如：Several of the stamps were of the unusual kind。其中几张邮票是不同种类的。The two boys are of the same age。这两个男孩年龄相同。She is of a different way of thinking。她的思维方式与众不同。These two kinds of article are of the same price。这两种物品价格相同。五、“be of+名词”也可以表示“来源、组成”。如：He was of a poor peasant family。他出身贫农家庭。The committee is of seven people。该委员会由7人组成。六、“be of+形容词的最高级”相当于one of。如：Mr。Wang is of the best teachers in our school。=Mr Wang is one of the best teachers in our school。王老师是我们学校里最好的老师之一。The English teacher of ours is of the quickest temper。=The English teacher of ours is one of the quickest temper。我们的英语老师脾气最急躁