The world has a big headache and it ----- by money .It began

The world has a big headache and it ----- by money .It began in America last year.
A.cause B.causes C.is caused D.are caused
答：C
译：这世界出了个很令人头痛的事.这都是钱惹的祸.是去年从美国开始的.
析：从这个by知道,为被动语态,主语为it,排除ABD
主要想问什么时候表被动但实义动词前不加be.
答:被动语态由助动词be(的某种时态形式）+及物动词的过去分词构成.
有时可不用助动词be而用get,同样能表示被动.