happy_to watch__ The Voice of China on Zhejiang TV.表示一种伴随状态
这句子关键看那个"happy"
B.watching：若用watching的话,happy应改成happily.（副词形容动词ing形式）happily_watching__ The Voice of China on Zhejiang TV.同样表示一种伴随状态
C.watched：若与sat做并列谓语,同样happy应改成happily（副词形容动词）
D.to have watched：表还是已看过,不符语意