At the computer operation test, one is supposed to stay at his own machine, keep his eyes on his screen, ______ to anyone.
—Beijing experienced _____ heaviest snowfall in ____ month of January .
We already have ______pencils, but we need two ____ pens.
Why are you leaving right now? You promised to stay ____ hours.
We asked John and Jerry, but ____ of them could offer a satisfactory explanation.
This book______18 articles , _______ three written by my father.