我想問下(乜咁岩呀)或者(乜咁喬呀)ge英文?

i would say the english translation would be:

'oh, what a coincidence!'

then you would perhaps use the phrase when you bump into people as:

'oh, what a coincidence to see you here!'

or:

'hey, it's such a coincidence that we are both in hk!'

係英文真係唔會好似我哋廣東人敢講. 較相似的只可說: Hi, I am surprised to meet you here.