There is (are) a pen and some books on the desk 此句中,为什么既可there is 又可用there are?

this is ------- -------- （pen).There are -------- (pen).填空 There is a pen and a pencil 还是There are a pen and a pencil there _ a pen and abook A.is B.are there is a pen on the table;那there are pens on the table可以吗? There ___ a pen and two pencils on the desk.用is还是are~There ___ a pen and two pencils on the desk.用is还是are~ 如何使用there is和there are比如说：there( )a desk in the classroom.there ( ) no ink in my pen. is there a pen and some books on the desk?肯定回答是yes,there is 还是yes there are There is a pen and three apples on the desk.为什么用is不用are? there is a pen and some rubbers on the table.这里应该用is还是are? there is a pen 对a 提问 请问:There ____ a pen and two pencils in the bag.填is 还是 are 急 There is a pen in his hand.和What are you?的同义句是什么? 可以说There is a pen here吗 There is a pen.的问句 选词填空[aren't are is are isn't ][ ]there a desk in your room?there[ ]a pen,but there is a pencilhow many rivers[ ]there?[ ]there any mountains?there[ ]many trees.there is only one. there is a pen and two books on the desk.还是there are a pen and two books on the desk?对这语法不懂,急用! There is (are) a pen and some books on the desk 此句中,为什么既可there is 又可用there are? This is a pen.(this)are pencily