是但既英文

是但既英文系乜野
Whatever ! = 是但啦
or, as you pleased, or, I have no idea 都得. 但 whatever 最常用:
Whatever you say = 是但啦, 你話點就點.
Whatever your prefer = (在餐廳) 是但啦, 你叫乜我食乜.

up to you
as you like
whatever

whatever or anything...

WHATEVER
whatever

As my experience, I would use '' whatever you like'' to have your Chinese meaning.
圖片參考：http://tw.yimg.com/i/tw/ugc/rte/smiley_3.gif

You just say:
Whatever
Right, whatever!

我公司的外国人就喜欢说WHATEVER啦.

1.casual; informal; random; arbitrary
2.at will; without concern; at (one's) pleasure; at random
3.(to a quest) as you please to

解釋:
隨便=是但
希望可以幫到您:)