arrive 是不及物动词，后面需要加介词in、at才能使用。
reach是及物动词，直接加地点就可以。
get是不及物动词，后面需要加介词to才能使用。
【arrive】
1.含义
vi.到达，来;发生
2.音标
英 [əˈraɪv] 美 [əˈraɪv]
3.用法
+in/on/at
4.例句
Fresh groups of guests arrived
新的客人接踵而来。
Any entry arriving after the closing date will not be considered
截止日期之后报名参赛的人将不予考虑。
Several long-awaited videos will finally arrive in the shops this month
几部让人翘首企盼的录像片终于将在这个月到货。
The time has arrived when I need to give up smoking.
我戒烟的时机已到。
These figures are arrived at on the basis of dentists 'receipts for 1991-1992.
这些数字是根据1991至1992年间的牙医收据统计得出的。
【reach】
1.含义
v.到达，走到;够…，抓…;完成
n.手脚能够到的范围;范围，区域;影响的范围，管辖的范围
2.音标
英 [ri:tʃ] 美 [ritʃ]
3.用法
reach sp.
4.例句
He did not stop until he reached the door
他走到门边才停下。
The process of political change in South Africa has reached the stage where it isirreversible
南非的政治变革已达到不可逆转的地步。
Judy reached into her handbag and handed me a small printed leaflet
朱蒂把手伸进提包，拿出一张小的印刷传单给我。
Can you reach your toes with your fingertips?
你能用手指尖碰到你的脚趾吗？
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？
【get】
1.含义
vt.得到;抓住;说服;受到（惩罚等）
vt.& vi.到达，来
vi.成为;开始;设法对付;获得利益或财富
n.生殖，幼兽;赢利
2.音标
英 [get] 美 [ɡɛt]
3.用法
get to sp.
4.例句
The boys were getting bored
男孩子们开始感到厌烦。
Half the pleasure of an evening out is getting ready
晚上外出时一半的乐趣在于出门前的准备。
I don't know if I can get it clean
我不知道自己是否能把它清理干净。
How did you get him to pose for this picture?
你想了什么办法让他摆姿势照了这张照片？
I might benefit from getting my teeth fixed
补牙可能对我有好处。