arise = to begin to exist or to develop [不及物動詞]
We can have another meeting if the need arises.
A heavy mist arose from the lake. 湖面起了濃霧
意思是:出現
arise 大多以抽象名詞為主詞。

rise = to move upwards or to a higher position [不及物動詞]
The aircraft rose slowly into the sky.
意思是:上升
但某件物品的價格上升是說成: rise in price或rise in value
Motor fuel rose in price as the war continued.

raise = to put something in a higher place or positon [及物動詞,會有受詞]
He could hardly raise the injured arm at all.
意思是:舉起某物件
You can raise your prices.
你可以提高售價.

1、發生；產生；出現 v.
Should the opportunity arise, I'd love to go to China.
要是有機會的話，我很想去中國。
Could you work on Saturday, should the need arise (= if it were to be necessary)?
萬一有需要，你可以在星期六工作嗎？
Are there any matters arising from (= caused by) the last meeting?
上次會議有沒有引出甚麼問題？

2、起床
We arose early on Christmas morning.
聖誕節早上，我們早早地起了床。