有關tenses 既問題(急!!!!!20點!!!!!!!)

Present Perfect Continuous
We use this tense for an action over the period of time leading up to the present.
Where have you been? I have been waiting here for two hour. (I’m still waiting.)
The action can be continuing in the present or the action may have ended recently.
I’m hot because I have been running. (I stopped running a short time ago.)

We often use for and since.
We have been living here for six months. (We are still living here.)
We can also use this tense for a series of repeated actions in the period up to the present.
I have been going to evening classes in Mandarin.

I have washed my car, so it looks a lot cleaner now.
(The tense focuses on the result of action.)
I have been washing my car, so I am rather wet.
(The tense focuses on the action that has been going up to the present.)

I have tried to phone you at least five times.
(When we say how much or how many, we do not use continuous.)

I have been trying to phone you all day.
(When we say how long, we normally use continuous.)

Past Perfect Continuous
We use this for an action that went on over a period of time before a past time.

The driver who died in the accident had been drinking.
(The action (drinking) went on over a period before the driver’s death.)

The volunteers had collected hundreds of dollars.
The volunteers had been collecting money all morning.
(The past perfect focuses on the result of action. The continuous form focuses on the action going on.)

When I saw you, you were playing golf. (I saw you in the middle of game.)
When I saw you, you had been playing golf. (I saw you after the game.)

Present perfect 未必指定時間入面就會做完
Have you ever ridden a horse?
(It can cover the whole of someone’s life up to the present.)
I have ridden a horse ten times.
(It can be used for repeated actions before now.)

2011-12-06 09:11:23 補充：
Past perfect

We use past perfect to describe an action which is completed before a time in the past. We can include a specific time reference.
We can use past perfect for the earlier action and past simple for the later.

By the time we arrived at the railway station, the train had left.

2011-12-06 09:18:41 補充：
For past perfect, 請看意見 section.