be (as) dull as ditchwater idiom informal (also be ditchwater dull)
无聊透顶，沉闷无趣
to be very boring
Before she arrived, the party was as dull as ditchwater. 在她到来之前，聚会无聊透了。
She is wrong when she says Shakespeare's plays are dull as ditchwater. 她说莎士比亚的戏剧无聊透顶，这话说得不对。
They might be ageing and ditchwater dull, but they're happy and deeply committed to each other. 他们可能年事已高，生活乏味，但他们很快乐，而且彼此深爱。