A group of young men hope that getting this kind of job will finally be the ticket to success.

 Sir, a Mr. Wang is waiting for you at the gate. ________ he come in or stay there?

—Where did you get this book?—I picked it up from a second-hand bookshop if you ______ know.

It is important to know about the cultural differences that        cause problems.

(2013·江苏南通市二模)We ________ have hurried all the way to the airport — the flight was called off because of the foggy weather.