灰尘在书架上不断堆积。

Dust keeps ___accumulating on the bookshelf.

她喜欢收集邮票，多年来一直在积累各种稀有品种。

She enjoys collecting stamps and has been ___accumulating rare varieties for years.

他的投资正在稳步积累利息。

His investments are steadily ___accumulating interest.