英文文法的問題

首先have became係錯的動詞...係have become.
然後討論since之後的意思是表達「自從」某時間開始，不過句子的內容是自己由讀middle school起便其實不同寫你係middle school student.因為除非入學校學英文的你不是學生，否則正常的英語不會這樣寫/講的。

不會寫成since I have become a middle school student是因為"已經剛成為"學生跟已經讀了六年英文的相對時空是矛盾的。即是前因和後果的動詞的時態"相同"但又有先後之分，所以令句子表達矛盾。
since I became a middle school student還可說在時空相對表達出"成為學生早過"已經讀了六年英文。但除非你現在已經不是middle school student這句才算完全正確，因為講法上好像表示middle school student這身份是過去了的事實。

較為正常的英語是:
I have studied English for about six years since middle school.

便可避免各種時空和人物的矛盾。

2) We have studied English for about six years since I became a middle school student.
have became is pp(past prefect tense) became is past tense.

1.(1)


Became 和 become分別不大 只是 became is past tense and become is infinitive
and perfect tense but became is past tense

2015-01-31 14:23:26 補充：
Sorry, 1. Is (2)

加一句，have became是錯的。
The three forms of become:
Become, Became, Become
Just like come:
Come Came Come
要知道就要記或查字典。

分別是 tense。

請看：

http://www.usingenglish.com/forum/threads/88689-Since-Past-Tense-Present-Perfect-Tense