He says they mistakenly believed the standard licenses they held were sufficient.是什么意思？

He says they mistakenly believed the standard licenses they held were sufficient.

他说他们曾经误以为有正规执照就足够了。

he

pron. 他，它，一个人；n. 雄性动物；

例句
Logic had prevailed and he had abandoned the idea.
最终理智占了上风，他打消了那个念头。

says

v. 说，讲(say的第三人称单数)；

例句
'When I was an adolescent,' says a thirty-one-year-old man, 'I thought girls held all the aces.'
“当我还是个毛头小伙儿时，”一个31岁的男人说，“我觉得完全是女孩子说了算。”

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。

mistakenly

adv. 错误地，被误解地；

例句
He mistakenly ascribes the expression 'survival of the fittest' to Charles Darwin.
他错误地认为“适者生存”是查尔斯·达尔文说的。

believed

v. 相信( believe的过去式和过去分词 )，认为，以为，对…信以为真；

例句
He believed in political activism to achieve justice.
他相信通过政治激进主义可以赢得正义。

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。

standard

n. 标准，规格，旗，军旗，度量衡标准，直立支柱；adj. 标准的，合格的，普遍的，一般的，公认为优秀的；

例句
The general standard of racing was abysmal.
竞赛总体水平极糟。

licenses

n. 执照( license的名词复数 )；v. 批准，许可，颁发执照( license的第三人称单数 )；

例句
He says they mistakenly believed the standard licenses they held were sufficient.
他说他们曾经误以为有正规执照就足够了。

held

v. 拿（ hold的过去式和过去分词 ），举行，保留；

例句
His car was held up and he was abducted by four gunmen...
他的车遭遇拦劫，随后他被4名持枪歹徒劫持。

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。

sufficient

adj. 足够的，充足的，充分的；

例句
The aircraft bumped along erratically without gathering anything like sufficient speed.
飞机忽上忽下，飞行很不平稳，根本未达到应有的速度。