Pieces of bamboo or wood ________ books between 2nd and 5th century AD.A. used to formed B. used to formC. were used to form D. used to beforming
While he was at _________ college, he took part in political activities, and was soon thrown into prison.
Supposing someone___________you had been lying, what would you do?
___ makes this shop different is ____ it offers more personal service.
_____ his sister, Jack is quiet, and does not easily make friends.
We do morning exercise every day, from which we ______ a lot.