问题详情

According to the Secretary-General, the American government has______.

A．tried its best to persuade the Congress to pass a bill on global warming

B．raised American people"s awareness about global warming

C．been searching for a successor to the Kyoto treaty

D．promised that the Kyoto treaty would expire in 2015

请帮忙给出正确答案和分析，谢谢！