完成時態for後加那些詞,since後加那些詞,要具體的,越多越好

題目：

完成時態for後加那些詞,since後加那些詞,要具體的,越多越好

解答：

for後加一段時間 ,但不能錯誤地認爲for加一段時間就是完成時.同樣 since 後加具體過去時間或過去時的句子,如果跟一般現在時時,since 表示「既然、由於」之意.
例 for three days
I have been here for three days.
I stayed there for three days. Now, I well remember that time.
I will stay there for three days there, then I will go to Australia.
Since three days ago, I have been here.