令他们吃惊的是，开车的居然是个6岁的小男孩。用英语怎么说？

令他们吃惊的是，开车的居然是个6岁的小男孩。

They were astonished to find the driver was a six-year-old boy.

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。

astonished

v. 使惊讶，使大为吃惊(astonish的过去式和过去分词)；adj. 吃惊的；

例句
Chris acted astonished as he examined the note...
克里斯检查记录时故作震惊状。

to

prep. 向，朝着，到，关于，属于；adv. 朝一个方向的，到某种状态，关闭；

例句
I suggest you leave it to an expert...
我建议你把它留给专家来解决。

find

v. 发现，找到，查明，发觉；n. 发现物，被发现的人；

例句
There are many people who still find the act of abortion abhorrent.
仍有很多人对堕胎行为表示厌恶。

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。

driver

n. 驾驶员，司机，驱动器，驱动程序，驱逐者，驱赶者，（高尔夫球）球棒；

例句
They were astonished to find the driver was a six-year-old boy.
令他们吃惊的是，开车的居然是个6岁的小男孩。

was

v. 用来表示某人或某物即主语本身，用来表示某人或某物属于某一群体或有某种性质（ be的过去式 ），在，存在，不受干扰；

例句
There was a terrible sadness in her eyes...
她眼神中流露出深深的悲伤。

boy

n. 男孩，少年，儿子，小伙子，家伙，服务员；

例句
Some parents believe a boy must learn to stand up and fight like a man.
有些父母认为男孩子必须学会像男子汉一样顶天立地，勇于抗争。