Because it's a bit boring
乏味───dull;它───it
coffin closed with a dull thud.───随着一声沉闷地撞击声，棺材合上了。
His letters are insufferably dull.───他的信乏味不堪。
party was stupefyingly dull.───聚会无聊透了。
You can pay a full-board supplement. . . but for heaven's sake don't do that . . . you see it's a bit dull eating in the hotel all the time.───你可以全包饭…..但看在上帝的面上，别那么做……你知道，总是在旅馆里吃饭有点儿死气沉沉。
All that glistens is not gold, any more than all that seems heavy or dull must automatically be lead.───发光的并不都是金子，沉重阴暗的也不都是铅。
Banking and asset management used to be perceived as fairly dull jobs, which did not attract a significant wage premium.───银行和资产管理过去一直被视为相当枯燥的工作，这并没有巨大的工资奖励。
After a dull start, it should brighten up later.
He had grown staid and dull.
His head hit the floor with a dull thud.
The first half of the game was pretty dull.
The countryside was flat, dull and uninteresting.