______ a man knows what is not to be done, will he succeed in doing what is to be done.
In the past few years, sea ice ____ in the Arctic as a result of global warming.
Peter told us the work would be finished by next month, _____ personally I doubt very much.
By the time our teacher arrives tomorrow, all the work _____,with which he will be content.
Don’t ask him how he is because if he starts talking about his health you’ll never _______ him.
The life of a high school student is usually active, exciting and full of fun, but it ______ be stressful sometimes.