英文解釋........

saying hi? are you sure?
如果你話 when i was chatting with [the] friend，中途佢話 "what have you been working on?" 咁就一定唔係 saying hi。
現時 saying hi 有好多方法，如：
What's happening? What's new? How's everything? How's life? What have you been up to? 亦可以講：What have you been doing?
方式真係太多，如果你話最近興埋 "what have you been working on?" ，我唔敢斷言佢唔係 saying hi，但就好視乎呢句說話幾時講。如果只係對話頭開始兩三個 turn 之中，可能係。
但如果已經係中途，就係問緊你最近做／忙緊乜野。
注意：樓上有說法話等於 What kind of works you have been doing? （你曾經做過那些工作?）有誤。work on something 係一個 phrasal verb，引 Oxford Phrasal Verbs dictionary for learners of English，意思係 to be busy with a particular activity, project, piece of research, etc.。亦唔係 past perfect tense，past perfect 係 had + past participle；呢句其實係 present perfect continuous，has/has + been + v-ing。

與我的朋友聊天是外國人和他說,你一直在什麼工作？ '有人知道意思是什麼嗎？ i 知道他正做某些事情" 說喂" 對我。但是i不能確信正好意思是嗎？

佢問你 ...做緊咩

What have you been working on?
= What kind of works you have been doing?
你曾經做過那些工作?

It is a past perfect tense, 包括 what kind of work you are doing now?

2007-08-30 09:37:45 補充：
In some occassions, this might equivalent to:Hi!How are you?or 你近日忙些什麼?等等之熟朋友見面語.

佢問"你做緊Ｄ咩...（咩職業）

個外國朋友問你"做緊吔"。