For the sake of enough time for study and rest, students are _____ from using cellphones in our school.
At the Olympic Games, only the athletes who have reached the agreed standard for their event will be ______ as competitors.
The scientist went to draw some money in the bank in a rush, onlythat he failed to take the ID card.
—Where did you come across your old classmate Jane? —It was in the supermarket _________ she worked _________ I came across her.
In the lecture, little Tom kept silent all the time unless _________ to express his opinion.
— How do you like the new book? —To be honest, it is a little difficult________.