There is a bird flying in the sky.这个是现在进行时?为什么flying前面没be

There is a bird in the tree. 对 a bird 划线提问 There is a bird（A.of B.to C.for)bird tree. There is a bird i＿＿ the cage . Is there a bird该成疑问句该什么改 There is a bird in the picture.的问句是什么? There is a bird in the tree 改为一般过去式 有一只小鸟在房顶上.There is a small bird There is a bird on the tree这句话对不对 There is a bird fly in the sky改错 there is a bird in the tree变为复数形式 Is there a bird near the window是什么意思? there is a bird in the sky 还是 there is bird in the sky那句对? 英语There be 句型后面必须接介词短语吗例如:There is a bird in the tree有没有there is a bird.这样呢? Look,there is a bird（）that tree.A in B on C atLook,there is a bird（）that tree.A in B on C at There seems a bird over there. In the tree there is a bird .可以改为:There is a bird in the tree .这2句有什么区别? There is a bird in the tree .It is s[ ].填单词 ( )you see a bird in the picture?This is a picture ( )my school.There is a river ( )there.