The Russian rocket designer has died. For many years, he ______ as an important assistant to the father of Soviet space program.  

John kept looking at the pretty girl, wondering whether he_________ her somewhere.

The damaged building           , so the people will have to look for other places to shelter themselves from the cold. 

So far this year we ________ a fall in house prices by between 5 and 10 percent.

—Time       . It’s likely that we will miss the bus.—Don’t worry. There are still 10 minutes left.