12/3.______has won the first prize in the Website Design Competition will be announced at awarding ceremony this evening.
A.Whoever B.who

16.Ms.Bond came to see the island and________.
A.stayed to enjoy herself B.stayed to enjoy it
我觉得两个都可。

31.I know______.
A.that you do your work not only efficiently but also that you have a high sense of resposibility
B.not only that you do your work efficiently but also that you have a high sense of reponsibility
C.that you are not only doing your work efficiently but you are having a high sense of reponsibility
D.that you do not only your work efficiently but also with a high sense of responsibility

请详细解释我列出的每个选项，谢谢！

12/3 B
whoever在名词性从句=anyone who，用在题中并不合适。句子要表达的意思是“谁获得一等奖”这件事会在今晚宣布，而非获得一等奖的这个人要被宣布，人怎么被宣布呢？

16 A
只有enjoy oneself或者enjoy和music之类的名词搭配的说法，而没有enjoy it（这里只可能指island）的说法

31 B
注意not only与but （also）后面的成分要从内容上并列、从结构上对称等价