变成否定句，一般疑问句，并作肯定和否定句。 （1）there is a bike under the tree。

否定句：There isn't a house。

一般疑问句：Is there a  house。

一般疑问句：实义动词使用助动词置前提问，be。

动词通常不用助动词而直接置前即可。

否定句：使用否定式助动词否定实义动词，be。

正如前面所述，回答一般疑问句时有肯定回答和否定回答两种方式，肯定回答以Yes起句，否定回答用No开头。但对一般疑问句的回答也不是一成不变的。肯定回答还可以用OK/Certainly等；否定回答可用Sorry等。

一般疑问句的结构

一般疑问句有两个家族。

第一家族为含be动词或情态动词的一般疑问句，其结构为：肯定回答用“Yes，主语+be\情态动词.”，否定回答用“No，主语+be\情态动词+not.”。be或情态动词和not可用缩写形式，主要有isn’t，aren’t，wasn’t，weren’t，can’t，mustn’t，needn’t等。

（1）there is a bike under the tree。
否定句： There isn't a bike under the tree.
一般疑问句：Is there a bike under the tree ?
肯定，否定回答： Yes, there is./ No, there isn't.

（2）there are some apple trees in front of the house。
否定句：There aren't any apple trees in front of the house
一般疑问句：Are there any apple trees in front of the house
肯定，否定回答：Yes, there are./ No, there aren't.

（3）there was a football match yesterday afternoon。
否定句：there wasn't a football match yesterday afternoon
一般疑问句：Was there a football match yesterday afternoon
肯定，否定回答：Yes, there was. / No, there wasn't.

（4）there were some people in the street
否定句：there weren't some people in the street
一般疑问句: were there some people in the street
肯定，否定回答：Yes, there were. / No, there weren't.

1，there isn't a bike under the tree
is there a bike under the tree?
2there aren't some apple trees in front of the house
are there some apple trees in front of the house?
3,there wasn't a football match yesterday afternoon
was there a football match yesterday afternoon?
4,there weren't some people in the street
were there some people in the street?