1． 动词 be 不仅有时态变化，而且与主语的数必须保持一致。如果主语是一系列事物！
　　第一个事物为单数可数名词，谓语动词则可用单数形式，如：
　　　There are some magazines on the desk.
　　　There was no school in the town forty years ago.
　　　There is only a teacher, five students and an old worker on the playground.

2． 这种句型中的主语是非限定的，不可用 this, that, the, these, those 等词修饰，也不可　
　　用"all + 名词"或与 every 构成合成词作主语。但在极少数情况下，可用限定性主语，
　　如：
　a. 在回答表示"存在"的问句时，如：
　　Is there anyone coming to the dinner?
　　Yes, there is Henry and there's also Jean.

　b. 当主语被形容词最高级修饰时，如：
　　There is the oddest-looking man standing at the front door.

3． 疑问式和否定式：把 be 移至 there 之前变为疑问式，在 be 之后加 not 或 no，变　
　　为否定式，如：
　　Are there any books in the other room?
　　There is a garage across the street, isn't there?
　　How many classrooms are there in your school?
　　There is not much water in the glass.
　　There is no smoking here.