keep it up保持优秀成绩；继续干下去；干得好
拓展：
(1)keep up不落后；维持，保持，使(斗志等)不低落
keep up with跟上……；向……看齐
(2)keep相关短语
keep a close/careful watch on 密切注意/监视
keep an eye on 留神；照看
keep away from (使)避开，不接近
keep a record保持记录
keep sth.in mind把……记在心里
keep off 使不接近，使避免
keep on 继续，持续
keep...out of 挡住，使进不去；不惹事
例句
I've been working twelve hours a day，but I shall not be able to keep it up.
我一直是每天工作12个小时，不过我再也坚持不住了。
We're on a winning streak—hopefully we can keep it up.
近来我们连连获胜，但愿能够再接再厉。
Her illness kept her away from work for several weeks.
她病得好几周都上不了班。
We must keep the enemy out of the country.
我们必须御敌于国门之外。
【链接训练】
If we can ________ this speed，we should arrive there in about two days.
A．keep up
B．keep on
C．keep to
D．keep with
【解析】 keep up意为“保持”；keep on doing sth.意为“持续做某事”；keep to“遵守(诺言)，坚持”。
【答案】 A
As a senior 3 students，if you want to get a good result，It's important to ________a good state of mind for the coming national entrance examination.
A．keep up
B．carry out
C．keep off
D．keep out
【解析】 句意为：作为一名高三的学生，如果想取得好的成绩，保持一个好的状态对即将到来的高考是很重要的。keep up意为“保持”，符合题意。carry out“执行”；keep off“远离”；keep out“使不进入”。均不符合题意。
【答案】 A