Jack doesn’t smoke now, but he _______ for almost twenty years.

Susan decided not to work on the program at home because she didn’t want her parents to know what she______ . 

As a teacher, he is ______ to work hard and must be strict in his work.

Either the ways or the time ____ yet, but you may ask the headmaster for some information．

—The twins will fly to New York with their parents this evening? ---No.In fact, their plane ___ from Shnaghai ahead of time.