do you still want them?----------do you want them ( )

yet一般用于完成时,而且是常用于否定句,如果用于肯定句,也多带否定转折的语气在,意思是还,有一定的感情色彩,这点作为一般用法就是这样的．
选C这里的语态很明显是一般现在时,所以用NOW现在．
你看下YET的用法介绍,这样你会更清楚．
yet常用于否定句和疑问句,但yet还有其他用法.1.用于否定句中,意思是还、尚、迄今、到那时”.例如 he is not yet here.他还未到.at three o”clock they had not yet decided whether to play basketball or not.三点钟时他们尚未决定是否去打篮球.2.用于疑问句中,意思是已经”.例如 is everything ready yet 一切都准备好了吗?3.与比较级连用,意思是更”.例如 you must work yet harder.你还需更努力地工作.4.与once ,again ,another 连用,意思是再”.例如 he has made yet another mistake.他又犯了一个错误.5.用于肯定句中,意思是仍然、还得”.例如 she is yet a child.她还是个孩子.6.用作并列连词时,意思是然而、可是”.例如 he studied hard yet he failed.他学习努力,可是考试仍未及格.