问题补充：
Taiwan is the Treasure Island of China and it is a part of China.
A. regard as
B. regarded as
C. regard to
D. regarded to
答案：
A. regard as
(答案→)B. regarded as
C. regard to
D. regarded to
解析：regard as把……认作；regard to关于，向……问好。句意：台湾被当做祖国的宝岛，它是中国的一部分。结合语境可知本句主语是动作的对象，故用被动语态，选B。
