catastrophic events such as volcanic eruptions.
C D
分析：B错，应改为to explain。 attempts后应跟动词不定式短语表目的，故将名词explanation改为to explain。
例：In the early 1960's the Civil Rights movement made great
A B
efforts for registering members of minorities to vote.
C D
分析：efforts to register, C错
C. 动词不定式的其他用法
(1) be to do 表示已安排好或者注定要发生的动作，属于将来时态的范畴
She and Anne are to meet at two o'clock.
(2)不定式的完成式为“to have done”，表示不定式的动作在谓语动作之前发生，这个完成式通常表示一般过去时
I am glad to see you.
I am glad to have seen your mother yesterday.
yesterday是一般过去时，修饰have seen.
(3) 形容词后面使用动词不定式，主动表示被动
It is difficult to decide.
