the tough outer skin of the beans

豆子坚硬的外皮

I bought a tin of beans .

我买了一罐豆子。

Two strains of bacteria are the key to making beans flatulence-free, Venezuelan researchers said.

两种细菌是让豆子不会造成肠胃胀气的关键，委内瑞拉研究人员说。

N-COUNT. 豆；豆子；豆荚. Beans such as green beans, French beans, or broad beans are the seeds of a climbing plant or the long thin cases which contain those seeds.