There are (two) libnaries in our school.
改单数：There is a library in your school.
否定句：There isn't library in your school.
一般疑问句：Are there any libraries in your school?
肯定回答：Yes,there are two.
否定回答：No,there aren't.
对括号提问(特殊疑问句)：How many libraries are there in your school?
回答：There are two libraries in your school.