1 . Supporters of sea exploitation argue that it is beneficial for humans, while o__________ claim that it tends to cause more problems. (根据首字母单词拼写)

2 . The ball was in the possession of their_________ for most of the match.

A．philosophy

B．tournament

C．opponent

D．association

3 . The president’s former adviser is now one of his strongest political_______(反对者). (根据汉语提示单词拼写)