I need your explanations. Thanks!
1a. I was studying when they came.
1b. I had been studying for two hours when before they came.
They (1a + 1b) have the same meaning, don't they?
The difference is the time signal (b): for two hours (emphazing the length of time).
2. I found the following prepositions in some articles:
in a university
at a university
at the Oxford University (certain university)
Are those correct? If yes, what is the difference between in a university and
at a university? Can we omit a to refer to any university in general?
Last edited by sio; 29-Dec-2008 at 06:40.
I had been studying (not I was studying) for two hours when they came. (just as you said, the mention of the duration of time, ie for two hours, determines the use of the past perfect continuous tense)
As for your second query - your understanding of the matter is spot-on (except for one thing - at/in Oxford University - no article needed)