Does Mary want to be an actor?
因为want是实义动词,变一般疑问句时,要用助动词do,而Mary是第三人称单数,所以do要变为does.若句子中有be动词,变一般疑问句时,把be动词移到句首,其他不变,最后加一个问号.如：She is a teacher.变一般疑问句为Is she a teacher?