he sometimes attend还是attends

Question

attend为什么不用attends
Their requirement is that every member attend at least one meeting per year.
既然every member是单数,为什么不用attends?

Answer 1

这是由于requirement 要用虚拟语气,这类的词还有suggestion等,完整的是--every member (shoud) attend --,shoud省略了.