Now the Great Wall is , so the Chinese authorities are working on a monitoring and warning system along the wall to preserve it in the future.
When the invader arrived, millions of people ____ from their homeland.
They are ___ the old houses in order to set up a new teaching building.
You should ___ the students instead of just telling them what to do.
It has rained for a whole day.But I think it's going to ___.
Her husband had ____ a large business during his lifetime.