✔ 最佳答案
This sentence is written by me.
I just copied it from the textbook and changed some words to avoid plariarism......
By the way, as per my understanding, both "when" and "before" are correct under certain circumstances.
We can use "when" to show the proximity of the two actions (i.e., the bell had been ringing for 3 minutes AT THE MOMENT the teacher came in, that is, the action "the teacher came in" immediate follows "the bell had been ringing for 3 minutes")
On the other hand, we can use "before" in case there may be an interval (let's say, 5 minutes) between the two actions. That is,
the bell rang (3 minutes) ~5 minutes........~ the teacher came in
Thank you for bringing up this question as I was not aware of this problem when making the sentence.
Please kindly let me know if what I said above is wrong......Thanks.
2011-02-23 11:53:03 補充：
Thanks for correcting me.
The original sentence is "The bell had been ringing for a good five minutes before the door was opened"
The explanation is that the opening of the door itself is a moment in the past and the bell had been ringing before that.
2011-02-23 11:53:33 補充：
In my opionion, the two actions may not necessarily happen at the same time, there may be an interval between the end of the first action and the second one. The bell rang some time before the door was opened, and the ringing of the bell lasted for 5 minutes.
Please let me know if I'm wrong. Thanks
