At the opening________of the school, our headmaster gave a short speech.
It was when I arrived home _____ I realized I had left my bag in the library.
You can complain, but I doubt _____ it’ll make any difference.
I won’t be able to answer any phone all the afternoon.I_____________ a conference.
The old couple have been married for 40 years and never once ___________ with each other.
This problem is far _____ me.I can’t work it out on my own.