Their arrival caused mayhem as crowds of refugees rushed towards them.是什么意思？

Their arrival caused mayhem as crowds of refugees rushed towards them.

他们到达后大批难民一拥而上，引起一片混乱。

their

pron. 他（她，它）们的，在提及性别不详的人时，用以代替 him 或 her；

例句
Their permissiveness toward their children reflects the wild abandon of their own lives.
他们对孩子的放任折射出他们自身生活的放浪形骸。

arrival

n. 到达，抵达，出现，登场，新生婴儿，到达者；

例句
Station staff announced the arrival of the train over the tannoy...
车站工作人员通过广播告知火车到站了。

caused

人为的；

例句
The report has caused acute embarrassment to the government...
报告将政府置于窘境。

mayhem

n. 骚乱，慌乱；

例句
Their arrival caused mayhem as crowds of refugees rushed towards them.
他们到达后大批难民一拥而上，引起一片混乱。

as

adv. 同样地，一样地，例如；prep. 作为，以…的身份，如

例句
As far as I can recall, Patti was a Smith.
我记得帕蒂是姓史密斯的。

crowds

n. 人群( crowd的名词复数 )，群众，一群，听众；

例句
They walked among the crowds in Red Square.
他们在熙熙攘攘的红场散步。

of

prep. 关于，属于…的，由…制成；aux. 助动词 [非标准用语、方言] =have [主用于虚拟语气]；

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

refugees

n. 避难者，难民( refugee的名词复数 )；

例句
The building housed 1,500 refugees and it burned for hours...
这幢住有1,500名难民的大楼燃烧了好几个小时。

rushed

adj. 匆忙的，贸然的；v. （使）急速行进，仓促完成( rush的过去式和过去分词 )，突袭，（使）仓促行事，催促；

例句
Horrified neighbours rushed to his aid as he fell.
他摔下来时，惊恐的邻居们赶忙冲过去救他。

towards

prep. 朝，向，对于，接近，为了；

例句
...absent fathers who fail to pay towards the costs of looking after their children.
那些不在子女身边、未能支付抚养费的父亲

them

pron. 他们，她们，它们；

例句
I take care of them to the best of my abilities...
我尽我所能地照顾他们。