The Chens have moved into a new flat，leaving their old house （having nobody inside）．
We don't （be not sure if something is true）the great achievements China has made in the past 40 years．
How calm and brave the command （飞行员）was to fly the plane back safely in such a dangerous situation！
In Western culture，"Black （星期五）"sometimes represents an unlucky day．
Look， our library is （东）of the classroom building． It looks modern．