There __ a book and two pens on the desk.答案是is.为什么

There __ a book and two pens on the desk.答案是is.为什么 There is a book and two pens on the desk. There( are )(a book)and (two pens)(on) the desk There are a book and two pens on the desk . there were a book and two pens on the desk There a book and two pens on the desk. There is a book and two pens on the desk.这句话是不是错了? 连词成句：there,a,book,and,pens,two,are,desk,the,on(.) There ______ a book, two pens and three pencils on the desk. There be句型There __ a book,two pens and some rulers on the de There are a pencil and two pens on the desk. There ________ a ruler and two pens on the desk.