It has been announced that students         remain in their seats until all the papers have been collected.

People ______ drive after drinking wine or beer according to the new laws. 

--- Shall I get one more cake fro you, David?--- Thanks, but you ______. I’ve had enough.

According to the rules and regulations, all payments _____ be made in cash in the shopping center.

Mike ________ his car, for he came to work by bus this morning