關於英文現在完成式since及have been的用法問題。?

1. It has been five years since I saw most of my relatives. (O)
It is five years since I saw most of my relatives. (O)

以時式來說，兩句都可以。

2.It is five years since he was a doctor.
--> 他"不當"醫生已經五年了。

紐約時報記者 Mike Schmidt 上月28日在高爾夫球場逮到一個機會，獨家採訪到美國總統川普。不過川普坐著而一開始 Schmidt 蹲在他腳旁，在報導中，他加注了這一句：

It’s been 20 years since I was a catcher in Little League, and a few minutes into our conversation my legs began to ache.
我當少棒捕手已經是二十年前的事，所以我們談不到幾分鐘，我雙腿就開始疼了。

另外有一首歌：

Way up in that sky
I look up and I wonder
If that's you passing by
It's been a while since I was your man
遠在天上
我仰望、我猜疑
是妳掠過嗎？
我已好久不是妳男人了

這種句型都表示「不是」 since 中所表示的身分了。

3.一個人曾經當過醫生（現在不是，表示經歷）：

He has been a doctor. （X）
這表示他目前還是醫生。

He had been a doctor. （X）
這表示在某個時間點之前，他已經是醫生。不代表他現在不是醫生。

要明確表示曾經是醫生，現在不是，要說：

He used to be a doctor.

1.It has been five years since I saw most of my relatives. (x)
It is five years since I saw most of my relatives.( 0)
= five years have passed since I saw most of my relatives.( 0)
because "saw"是 瞬間動詞


2.It is five years since he was a doctor. 他 不 當 醫 生 已 經 五 年 了
It has been five years since he was a doctor. 他 當 醫 生 已 經 五 年 了

because 動 詞 "was" 是 狀 態 動 詞

since&have been:-eg:-
(1)It has been five years since I last saw most (of my) relatives
=I have seen most (of my) relatives since we were to a point of time in the past/to a period of time since 5 years ago.
(2)He has already retired as a doctor 5 years since.
(3)He has been a doctor ever since 5 years ago. It is five years since.

0. 一般人(台灣人)對"完成式"都有很深的誤解.完成式主要是用來"強調"一段有意義(在這裡強調)的(但是並不一定會有明確的說明)時間的完成.

1. 不能 - 既然要說明"完成了5年"就應該用完成式

2. 不能 - 既然要說明"完成了5年"就應該用完成式

3. 應該用: He had been a doctor (for 30 years) before started this company.

It has been 3 years. 是 it is 3 years. 的完成式 所以2者都是合文法的句子.例子:

It is 30 years that I was sentenced in the trial.

1. 不能
2. 不能
3. 兩個都錯

1. 先說假如如你的寫法的錯誤原因：
It is five years這字句/句子本身的句式表示"it is"之後的是一件"東西"，five years詞性上並不是"一件"東西或"一件"事。當中句括five years是眾/多數，因此it "IS"便是錯，而你亦不可改作They are five years吧？［英文句式就說到這裏，因為句子要表達不單單是＂一件＂事，或看來你視為＂一段＂時間（看作是單數），而是重點是＂曾經和已經＂。
２. 你寫的句錯的，所以只用原句式寫He has been five years since he became a doctor.意思是他已經當了醫五年了。
３. 曾經當過醫生（現在不是)就簡單地過去了：He was a doctor.便有他曾是(現已經不是)"任何身份"都可以通用的。