a number of：许多的.；
例句：
There were a number of errors and omissions in the article.
这篇文章中有多处错误和疏漏。
A number of people have been employed to deal with the backlog of work.
已雇来一些人处理积压的工作。
They were planning to solicit funds from a number of organizations.
他们正计划向一些机构募集资金。
This model comes with a number of optional extras.
这一型号有一系列可供选择的附件，价格另计。