Unless _________ by the police, you should keep silent over the accident.

When he was a boy, he used to go there and watch _____.

My parents are ________ to live in the countryside,where the air is clean and the vegetables are fresh．

(2013·吉林长春三校高三调研)China is expected to export 1 billion mobile phones this year, ________ by a surge in demand for smartphones worldwide.

During an interview, journalists always prepare the next question _____ on the interviewee says.