有關have/has been的問題

第一句係passive 黎架,
因為隻牛係因為--某一樣野--而死,點講le....
即係可能係細菌,可能係人為,可能係老死,
總之呢個動作唔係佢自己發出o既..
has been後面如果用ing就會變左現在完成進行式,
即係個動作由以前一路做到而家都仲做緊,
所以唔係咁用lor~

第二句同第一句唔同,因為sick如果解釋病o既話,
佢唔係一個verb黎架,佢係一個adj,
所以冇sicking呢個字,如果用sicking就會變左另一個意思,
has been係現在完成式,即係由過去到現在都係咁
即係個bb由過去一個月病到而家.

最後一句都係現在完成式,
意思即係而家呢一代,有好多年青人吸毒,
係由呢一代開始,直到而家有好多人吸毒,
都係由過去到而家發生,
因為呢個nowadays可以表示到而家,或者由過去到而家o既意思,
所以呢句可以講
nowadays, there is a lot of teenagers having drugs.都得

希望幫到你^^

2008-03-07 22:53:12 補充：
係呀,我有提sick係adj唔係verb呀,不過真係唔記得左dead都係adj,thank you thank you^^~
大學不愧係大學a~haha~!

第一個答案比較好，要補充的是： dead 及 sick 是 adjective 不是 verb。

第二個答案提到 my cow has been dead for two years 是 passive 是錯誤的。

你所寫的句子都是用動詞to be，所以在present perfect tense時便要寫成have/has been:
My cow is dead.
>My cow has been dead for two years.

My baby is sick.
>My baby has been sick for a week.

There are a lot of teenagers having drugs.
>Recently, there have been a lot of teenagers having drugs.

如果have/has been之後接上的是-ing形動詞，那就是present perfect continuous tenses:
I work on this project. (stating a fact)
I have worked on this project for two hours. (stating a fact that started in the past and is still happening)
I have been working on this project for two hours. (like the above sentence, but this one stresses more about the continuous nature)

如果have/has been 之後接-ed形，那就是present perfect tense - passive voice:
I have told Mary that she needs to show up at 4.
>Mary has been told that she needs to show up at 4.

Mary has informed me that I will be invited to the party.
>I have been informed that I will be invited to the party.