否定就直接在be后面加上not 就可以了.比如
There are some apples.否定是There are not any apples.
there is a bird in the tree.否定是there is not a bird in the tree.
疑问句直接吧 be 提到句子的最前面就可以了,一上面的为例
are there any apples?yes,there are./no,there are not.
is there a bird?yes,there is./no,there is not.