I heard the news that a new student would join our class 为什么用would不用will?

I heard the news that a new student would join our class 为什么用would不用will?
I heard the news that a new student would join our class 为什么用would不用will?

I heard the news that a new student would join our class 为什么用would不用will?
前面是heard,要跟主句时态一致

因为过去听说的，所以用过去将来时。假如是hear,就用will。这是主从时态一致原则之一。