他们在讲下流故事。用英语怎么说？

他们在讲下流故事。

They were telling dirty stories.

they

pron. 他/她/它们，人们，大家，政府，当局，她们；

例句
The storms had abated by the time they rounded Cape Horn.
他们绕过合恩角时，暴风雨已经减弱。

were

be的过去时复数和第二人称单数形式，有时代替 was,用于条件从句、动词 wish 之后等；

例句
Shops, houses, and vehicles were set ablaze.
店铺、房子和车辆全都陷于火海。

telling

adj. 有效的，显著的，生动的，说明问题的；v. 讲述( tell的现在分词)，告诉；

例句
Pete was telling them an anecdote about their mother...
皮特正在给他们讲一件他们母亲的趣闻。

dirty

adj. 恶劣的，肮脏的，卑劣的，下流的；vt. 弄脏，污染，使名声受玷污；vi. 变脏，污染；

例句
...the notorious Montonero guerrilla group who did battle with the army during the dirty war...
曾在那场肮脏的战争中与这支部队交战的臭名昭著的蒙特内罗游击队

Stories

n. 故事( story的名词复数 )，（任何结构、构造的）层，<口>谎话，<美>楼层；

例句
Washington has been abuzz with stories about disarray inside the White House.
整个华盛顿都对白宫内发生的混乱议论纷纷。