单选题 People seldom trust him since he usually fails to______his promises.
【正确答案】 A
【答案解析】[注释] 本题需弄清以keep为中心的四个短语动词的意思。A项keep to意为“遵守，坚持”,B项keep on意为“继续……”，C项keep off意为“让开，挡开”， D项keep up意为“保持，继续”。根据题意，A为正确答案。