请将相应的内容填入表中
It has been ______ that 2012 Olympic Games will be held in London. [ ]
A. confirmed
B. confused
C. confessed
D. confined
在体内可转化为半胱氨酸的必需氨基酸为()
A.异亮氨酸
B.酪氨酸
C.蛋氨酸
D.色氨酸
E.苯丙氨酸