.— Why was Professor Johnson unhappy those days?— Can’t you see it clearly? The only reason was that the theory he stuck to________ wrong.
_____ we have finished the course, we shall start doing more revision work.
I’ll never forget the days ______ I spent on the farm.
I meant to help him . ______, he didn’t accept my offer.
Several months later, he found his deskmate very difficult _______.
In order to make up for the lost time, they are working ______.