No such authorization ______ be given without the president’s written permission.

If we work hard with a strong will, we _____ overcome any difficulty, however great it is．

 It's high time that we students ______ even harder at our lessons as the national entrance examination is coming nearer. 

 Peter ______ be really difficult to deal with at times even though he’s a nice person in general.

 Good luck to you, and _____ all your wishes come true.