the number of ．意思是“………的数字／数目”，介词 of 同其后名词构成介词短语，修饰 the numbe r ．当它作主语时，谓语动词用单数。

1、 The number of business failures has risen .企业倒闭的数量增加了。

2、 The number of independent firms decreas ed from 198 to 96.

独立公司的数量从198个减少到了96个。

3、 The drug increases the number of red cells in the blood , enhancing oxygen uptake by 10 percent .

这种药增加了血液里的红细胞数量，从而将摄氧量提高了10%。

4、 The number of unemployed people in Pola nd has grown by more than a quarter in the la l st month .

上个月，波兰的失业人数增长超过了1/4。

the number of是什么什么的数量 ，所以主要是修饰名词 。比如说：The number of the students in our class is 40.