have the final say 说了算;有最终决定权;拍板

【例句】
But he only agreed to take the job if they let him have the final say.
不过他说只有他们让他有最终决定权，他才会接受这个职位。

How can only one person have the final say on such an important matter?
这么大的事怎么能一个人说了算？