15. (2018青岛)We have worked so long. Shall we stop ________ a rest?
A. have  B. to having  C. having  D. to have
15. D【解析】考查动词不定式。句意：我们已经工作这么久了。我们停下来休息一下好吗？根据前半句“We have worked so long”可知表示停下工作去休息。stop to do sth.停下来去做某事。故选D。