Being a gun, the old man's action became jittery.是什么意思？

Being a gun, the old man's action became jittery.

因为被枪指着, 那个老男人的动作变得(战战兢兢的,神经过敏的).

being

n. 存在，生物，人，要素，本质；

例句
...expensive make-up that we saw being advertised by a beautiful model...
我们所见的由一位漂亮模特代言的昂贵化妆品

gun

n. 枪，发令枪声，受雇杀人的枪手，喷射器；vt. 射击（某人），给…加大油门，打猎；vi. 用枪打猎；

例句
He stood with the gun in his right hand and his left hand steadying his aim.
他站立着，右手举枪，左手稳住枪对准目标。

the

art. 指已提到的人（物），指说话人与听者已知的人（物），用于独一无二的事物前，与形容词最高级和序数词连用；

例句
He did have a real knowledge of the country...
他对该国的确知之甚多。

old

adj. 老的，古老的，以前的，（用于指称被替代的东西）原来的；n. 古时；

例句
She was old enough to absent herself from the lunch table if she chose...
她长大了，可以自己做主不来吃午餐了。

action

n. 行动，活动，功能，作用，手段，[法]诉

例句
The government is taking emergency action to deal with a housing crisis...
政府正采取紧急措施解决住房危机。

became

v. 变为，成为（ become的过去式 ）；

例句
It became very clear that the incident was not just an aberration, it was not just a single incident.
事实已经很清楚，这件事不是偶发的，它并不是一起孤立的事件。

jittery

adj. <口>紧张不安的；

例句
International investors have become jittery about the country's economy.
国际投资者已对该国的经济状况感到紧张不安。