Intelligent people need never work hard to be successful in the field where they are engaged in,___they?

选D
解释：反义疑问句中主句的never,not,little,few等表示否定的词,在疑问的部分都要用肯定.所以排除AB.下面我们来看D.need这个词有两个用法：情态动词和实义动词.做情态动词时后面接动词原形,做实义动词时一般有need to do sth.的句式.前句中need是情态动词,而不是实义动词.因为后面接了动词原形work.由此可见选D.
打字打了好久,楼主选我吧,我学习很好的哦!