The desks and chairs are made of wood.这句话中的介词of是不是可以变为by如果可以,为什么如果不可以,理由是什么?

the desks and chairs are (我们的) the student,desks are blue and the chairs ane ble, chairs/were/and/The/desks/new/the(连词成句) There are forty desks and chairs in the classroom. ( )(有) forty desks and forty chairs in the classroom chairs,the,clean,desks,and,let's 整理成句 chairs,the,clean,desks,and,let's 整理成句子 _____they_____the desks and chairs in the library?Yes,______ ______ he‘ll make the desks and chairs out （ ）wood all the chairs and desks are （ ）groups. Please count the desks and chairs.修改病句 Please count the desks and chairs.哪错了/ groups,all,chairs,are,in,desks,the,and造句1 改错;Please count desks and chairs.请说明原因,改错;Please count desks and chairs.请说明原因.另,please count the desks and chairs和please count the desks and the chairs.的区别! There-----40 desks and chairs.------- ---------a bookcase, trips,real,field,study,things,on the,we(.)groups,all,chairs,are,in,desks,the,and(.) -Are the girls playing games?-No,they___.they____(clean)the desks and chairs. the students_______often ______(tell) to take care of their desks and chairs.改为被动语态.