10．The house   we used to live    has been rebuilt．

When exposed to stress, in ________ form, all of us react both chemically and physically.

______was known to all,William had broken his promise ______ he would give us a rise.

It is already well understood___________ causes the global warming.

After Yang Liwei succeeded in circling the earth ,_______our astronauts desire to do is walk in space .