I wondered what difficulty he had _________ the plan?
The rules of our school don’t allow _______ at school. That is to say, nobody is allowed _______ here.
Our classmates _________ the losing team of our class and our team won the game at last.
There were two teachers named John ________at our school, which made some of our students ________.
They always communicated with each other on the Internet, but they never met him _______.
A ______ is something we buy to help remind ourselves of a place we have visited.