Question

【题目】Public service ads，also PSAs，often _________ for free，_________ to educate people about health，safety or any other problem that affects public welfare.

A. run；meant B. are run；are meant

C. are run；mean D. run；are meant

Answer 1

【答案】D

【解析】非谓语动词和固定搭配。句意：公益广告一般是免费播放，它们旨在向人们传递有关健康、安全或任何其它影响公共福利的问题等方面的知识。逗号之间的部分是插入语，是一个过去分词短语，PSAs和run之间是动宾关系，即公益广告被播放，应该用过去分词，排除B、C；be meant/intended for sth/to do sth旨在......，相当于be aimed to do sth，故选D。