You are ________ to shut off your mobile phone when having a meeting.

Where’s the old blue bag- I’m not sure, but it ______ be thrown away. It be somewhere in the house .I saw it yesterday.

Why do you like wearing this old sweater —I like wearing this old sweater it was made by grannny by hand .

With Halloween approaching, there exists a real concern among parents and teachers __________ trick or treating will become a seriously anti-social activity.

Three years has passed, but we can’t forget the people _________ helped me a lot in the past.