Seeing their teacher _______ into the classroom, they stopped _______ at once.
You never eat burnt barbecued meat, _______?
、This question is ______ easy, all the students can answer the question.
We should talk in English as ______ as possible.
---Is Mr Hu in the reading room? ---No, he _______be there. He has gone to Tianjin.
Some of her best loved photos are ___ display in this exhibition .