keep up 是坚持的意思,keep doing sth也是坚持的意思.二者有什么区别么

keep up坚持; 维持; 继续; 不低落; 不为(疾病等)所屈;坚持不懈常用短语：keep up with跟上,不落后; 与。。。并肩前进与。。。保持接触keep it up不松劲,照原样继续下去keep one's end up精神饱满地对付keep up appearances装门面keep up appearance【法】虚饰外表keep up one's spirits振作精神keep up to date使记到最近时期；使跟上时代keep one's chin up 不气馁例如：The house is becoming too expensive for them to keep up。他们的房子维修费用贵得越来越修不起了。keep doing表示“不断（老是）做某事”的意思,强调动作连续不断,每隔一会儿发生,这时两者可以换用。不同的是keep doing中的doing是动名词,作宾语。例如：John always kept (on) asking questions。约翰总是问个不停。News of successes keeps (on) pouring in。捷报频传。keep doing还可表示连续不断的动作或持续的状态。例如：We kept working in the fields in spite of the rain。尽管下雨,我们还是坚持在地里干活。Why do the dogs keep barking?这些狗为什么不停地叫?