There is an apple on the desk 这句的主语是什么?同志们问一下 There is an apple on the desk .的主语是啥?

There is an apple on the there is an apple on the table 改为复数形式 There is an apple on the tree.(改为复数） is there an apple on the table?否定回答 is there an apple on the table.否定句 There is an apple on the table.否定句 there is an apple on the desk同义句. There is only an apple on the table 改同义句 There is __ __ an apple on the There is only an apple on the table.There is ____ ___ an apple on teh table. there is not an apple on the desk 的同义句There isn't an apple on the desk.（填一词）There is -------------------------apple on the desk. there is an apple on the table.it is yours there is an apple ____ _____on the table There is an apple on the desk改为--- --- --- --- there on the desk 句型转换 There is an apple on the table.(根据an apple提问） （ ）（ ）on the table? there is a pen in my pencil-box.there is an apple on the table. 改错 I have an apple .An apple is very sweet Look There is a orange on the table This is an orange. There is apple on the table. WThis is an orange.There is apple on the table.What are you doing?译中 there is an apple on the table 对句中的an 进行提问 英语语法句子结构问题There is an apple on the desk.中,on the desk是状语,an apple是主语,is是谓语,那there是什么?