keep up with什么意思解释？

keep up with的音标：keep up with的英式发音音标为：[ki:p ʌp wið]keep up with的美式发音音标为：[kip ʌp wɪð]...

He lengthened his stride to keep up with her.他迈大步追上她。The two saleswomen were busily trying to keep up with the demand.那两名女售货员正忙着接待顾客。She was skipping to keep up with him.她连蹦带跳地走着，好跟上他的步伐。...