Who ________ a theory about black holes?

The birds flew ___ the direction of the south

On April 14, 2010, many people dressed in black with white flowers ______ their chests observed three minutes of silence in memory of the victims in Yushu Earthquake .

So sudden____thatthe enemy had no time to escape.[ ]

Experience is not the things happening to you; it’s the way you do with happens to you.