三个单词都有“到达”的含义：
在表示到达某个地方时，arrive和get意思类似，get常用于口语；而reach还有比喻含义。
reach到达（及物动词，可直接后接名词或副词。）
后面直接，接表示地方的名词例如：
They reached Beijing at nine.
他们9点钟到达北京。
He reached home in the evening.
他晚上到的家。
He reached Cambridge shortly before three o'clock.
他快到3点的时候抵达了剑桥。
《柯林斯高阶英汉双解学习词典》
When the bus reached High Holborn, Tony rang the bell and they jumped offtogether
当公交车到达海霍尔本站时，托尼摇响了铃，他们一起跳下了车。
《柯林斯高阶英汉双解
注：reach 之后也可接 here, there, home 等词.如：
When did he reach home yesterday?昨天他什么时候到家?
时候到家?
The news reached China apace.消息迅速地传到中国。
They didn't reach the border until after dark.
他们天黑以后才到达边境。
I hope this letter reaches you.
我希望你能收到这封信。
He did not stop until he reached the door...
他走到门边才停下。
If they followed the road, they would be certain to reach a village
如果他们沿着这条路走，就一定会到达一个村庄。
《柯林斯高阶英汉双解学习词典》
We reached the station just in time. 我们及时赶到了火车站。
reach主语可以是物，而且能灵活运用于比喻含义例如：The Belgian player Eduardo Masso has reached the final of the Dutch Open in Hilversum
比利时选手爱德华多·马索进入了在希尔弗瑟姆举行的荷兰公开赛的决赛。
《柯林斯高阶英汉双解学习词典》
We're told the figure could reach 100,000 next year.
我们得知明年这一数字可能达到10万。
She has reached the limit of endurance.
她已达到了忍耐的极限。
The rumours eventually reached the President.
传闻最终引起了总统的注意。
The conflict has now reached a new level of intensity.
冲突现在已经达到了新的激烈程度。
Daytime temperatures can reach 40˚C.
白天的气温可以达到40摄氏度。
He first reached the finals in 2000.
他于2000年第一次进入决赛。
The negotiations have reached deadlock.
谈判陷入僵局。
reach a conclusion/decision/verdict/compromise
得出结论；作出决定 / 裁决 / 妥协
They are meeting in Lusaka in an attempt to reach a compromise.
他们在卢萨卡举行会谈试图达成妥协。
《柯林斯高
He managed to reach a partial agreement with both republics.
republics.
他设法与两个共和国都达成了部分协议。
He is very keen to reach agreement with the US on reducing long-rangenuclear missiles.
他很想和美国达成协议，减少远程核导弹的数量。
《柯林斯高阶英汉双解学习词典》
Politicians again failed to reach an agreement .
政治家们又一次没有达成一致。
‘Grab the end of the rope.’ ‘I can't reach that far!’
“抓住绳子头。”“我够不着！”
Can you reach the light switch from where you're sitting?
从你坐的地方够得着灯的开关吗？
Is the cable long enough to reach the socket?
电线够得着插座吗？
Do you know where I can reach him?
你知道我在哪儿能跟他联系上吗？
Has the doctor told you how to reach him or her in emergencies?
医生有没有告诉你发生紧急情况时怎样与其取得联系？
《柯林斯高阶英汉双解学习词典》
News of his affair eventually reached her ears.
Can you reach your toes with your fingertips?
our fingertips?
你能用手指尖碰到你的脚
If I see her, I'll tell her you've been trying to reach her.
trying to reach her.
如果见到她，我会告诉她你一直在尝试联系她。
《柯林斯高阶英汉双解学习词典》
After much consideration, they arrived at a consensus.
再三考虑之后，他们达成了共识。
To arrive at a solution is the most urgent task.
找到解决办法是当务之急。
arrive
arrive+in＝较大的地方，如城市例如：
Ｈorace arrived in Ｅurope yestrday. 霍勒斯昨天抵达了欧洲。
He arrived in Shanghai last night. 他昨天晚上到达上海。
arrive+at＝较小的地方，如乡镇例如：
One day a letter from my father arrived at the school. 有一天学校收到了我父亲的一封信。
arrive
不及物动词，表示到达较大的地方（如城市、国家等）时后接介词 in，而到达较小的地方（如机关、学校、商店等）时则后接介词 at。
〔例证〕
The American visitors arrived in Beijing yesterday
We arrived at the station five minutes late. 我们到车站晚了5分钟。
They will arrive in Paris next Monday. 他们将于下周星期一到达巴黎。
xt Monday. 他们将于下周星期一到达巴黎。
You must arrive at the airport two hours early.
你必须提前两小时到达机场。
如果后面有地点副词，不用介词例如：
Ｉ suppose he will arrive home in the evening. 我想他晚上会到家的。
Get（不及物动词，须后接副词或介词 to。）
get+to，并且常用于口语例如：
I think the car will just last out till we get to London.我想这车能坚持到我们到达伦敦。
He got back home yesterday.
他昨天回到了家。
How did he get there in such a short time? 他是怎么在那么短的时间到那里的？
When we got to the park,it began to rain. 我们到达公园时,就开始下雨了。
She got to London this morning.
她今天早晨到达伦敦。
如果后面有地点副词，不用介词例如：
When did you get there? 你是什么时候到那里的？
She got there at 4 p.m.
她下午4点到达那里。
We got 〔arrived〕 here last night. 我们昨晚到达这儿。
get ， arrive是不及物动词， 带宾语时用get to 、arrive in/ at +地方， 如果跟here,there， home，就直接用get/ arrive there/home, 不要介词。 arrive in+大地方; arrive at+小地方
reach是及物动词， 直接带宾语 reach Beijing
如果单独使用，不带宾语时， 用arrive :When did you arrive?
用arrive :When did you arrive?