1.“主過從過”原則:主句是過去時態(tài),從句一般也用過去的某種時態(tài)
When I was a student,my teacher often told us that time and tide wait for no man.
當我還是學生的時候,老師常常告訴我們,歲月不等人。
I knew he could help me if he was free the next day.
我知道第二天他有空的話會幫助我的。
2.“主將從現(xiàn)”原則:時間狀語從句和條件狀語從句中,主句是一般將來時,從句則用一
般現(xiàn)在時或現(xiàn)在完成時
I’ll tell her the good news when she comes back.
當她回來的時候,我將把這個好消息告訴她。
Don’t get off the bus until it has stopped.直到車停穩(wěn)再下車。
If it doesn’t rain,he will come here on time.如果不下雨,他會按時來這兒的。
You’ll make progress if you keep working hard.如果你繼續(xù)努力,你就會取得進步。
3.“since+過去時間”句式中,主句通常用現(xiàn)在完成時,從句用一般過去時。
He has worked at the factory since he came here.
自從他來到這兒,他就一直在這家工廠上班。
Since I left college,I have not seen him.自從我從大學畢業(yè)以后,就沒有見過他了。
4.“It is+段時間+since+從句”中,since從句要用一般過去時
It’s a long time since we met last.自從我們上次見面以來已經(jīng)有好長時間了。
It is ten years since she left me.自從她離開我已經(jīng)十年了。