The crew-members were Syrians.是什么意思？

The crew-members were Syrians.

乘务员是叙利亚人。

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。

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。

Syrians

n. 叙利亚人( Syrian的名词复数 )；

例句
The Syrians have not yet accepted an invitation to attend...
叙利亚人还没有接到出席邀请。