使用there be句型描写学校和以前的句子，可以通过对比现在和过去的情况来表达。以下是一些例子：

现在学校的情况

"My school is very big and very beautiful. There are three buildings in our school."

"I'm in a new school. The new school is bigger than the old one. There is a gate and a yard in the new school."

"Five years ago, our school was very small. There was only one building with two floors. There were twenty teachers and seven classes. But now in our school, there are three buildings and there are 14 classes. And there is a big playground behind the classrooms, too."

过去学校的情况

"But before there was a building."

"the old school is not. There are lots of flower beds in the school yard, those flowers are very beautiful, but the old school is not. There is a big swimming pool. We can go swimming, but there is no old school."

通过这些句子，可以清晰地看到学校和以前相比的变化。