. (2010·江西名校模拟) —I’ve heard they went skiing in the mountains last winter.                           —It ______ true because there was so little snow there then. 

The bus ____ at six, but it arrived an hour later.

—Where did you get this book?—I picked it up from a second­hand bookshop if you ________ know.

 —Must I wait for you here?—No, you ______. 

 Don’t worry about your future. As long as you try your best, a great future ________ wait for you on your way.