when引导的是很么从句，是什么结构，从句为什么没谓语

Question

the total number when employees in the companies is now over five hundred

Answer 1

when
可以引导很多从句：
1.宾语从句：例如
I
don`t
know
when
he
left
here.我不知道他上面时候离开的.此时when作连接词引导宾语从句.
2.定语从句：例如
He
left
his
hometown
in
that
year
when
his
father
died.他在他父亲死的那一年离开了他的家乡.此时when作连词修饰that
year,引导定语从句.
3.状语从句：例如
He
will
go
to
the
doctor`s
when
it
is
sunny.当天晴时,他就会去看医生.此时when引导状语,意思是“当...时候”.
4.主语从句：例如When
he
left
here
is
a
question.他上面时候离开这儿的还没有人知道.此时when引导主语从句,意思是“什么时候”