keep up3（及物，可分）继续
Dick and Helen kept up correspondence with each other for several years.迪克和海伦保持通信好几年了。
Two powers attempted to keep up pressure on that small country until she gave in.两个强国企图不断向那个小国施加压力，直到她让步为止。
Keep it up；don't give up halfway！干下去，别半途而废！
keep up with1（及物，不可分）跟上
I ran fast，but she kept up with me.我跑得快，可是她赶上来了。
We must try to keep up with the rapidly developing situation.我们必须努力跟上飞速发展的形势。
It is very expensive to keep up with the fashion.赶时髦是很费钱的。
The teacher gave him some coaching to help him keep up with the class.老师对他进行辅导，帮助他跟上。
keep up with2（及物，不可分）（通过写信等）和…保持联系
You can keep up with him by telephone.你可以打电话跟他联系。
They have kept up with foreign publishers since 1995.自从1995年以来，他们一直同外国出版商保持着联系。
Have you kept up with your elder sister recently？你最近跟你姐姐有联系吗？
I kept up with him while he was in Shanghai by telephoning him once a week.他在上海期间，我每周都给他打一次电话保持联系。
key...up（及物，必分）使（人）紧张
Speaking to a large audience always keys her up.她当众讲话总是感到紧张。
Everyone was keyed up waiting for the game to start.每个人都感到紧张，等待着比赛开始。
The children were keyed up at the show of high-wire walking.孩子们在看走钢丝表演时感到紧张。
kick against ［at］（及物，不可分）反对
Some men seem brave when kicking against an authority.有些人在反对权威时显得勇敢。
I kick against wearing stockings.我不喜欢穿长袜。
kick out（of）（及物，可分）开除
He was so lazy that they kicked him out.他太懒，以致被他们解雇了。
The boss will kick out Holm if he is late again.霍尔姆若再迟到，就会被老板解雇。
That officer must be kicked out.那位军官必须革职。
Malden was kicked out of the club.马尔登被开除出了俱乐部。
kill off（及物，可分）杀光（生物）
The frost killed off most of the injurious insects.这场霜消灭了大部分害虫。
If the enemy continue to resist stubbornly，kill them off.敌人再顽抗，就消灭他们。
Some species have been killed off.有些物种已经消灭。
knock about（不及物）漂泊
Cox is such a man knocking about from place to place and never settling down.考克斯是个到处流浪、居无定所的人。
They knocked about in the streets when they ran out of money.他们把钱花光了就流浪街头。
Levie knocked about in a strange land at the age of fifteen and since then nobody has known his whereabouts.利维15岁就漂泊异乡，从那以后谁也不知道他的下落。
knock at ［on］（及物，不可分）敲
Someone is knocking at the door.有人在敲门。
Did you hear someone knocking at the window just now？你听见刚才有人在敲窗户吗？
knock off1（不及物）停止工作
When do you knock off？你什么时候下班？
They knocked off at four today.他们今天4点下班。
The bell rang and we knocked off for lunch.钟响了，我们停止了工作吃午饭。
knock off2（及物，可分）停止（工作）
When do you knock off work？你什么时候下班？
You've been writing all day long.It's time you knocked your work off.你已经写作了整整一天。该停止工作了。
knock off3（及物，可分）很快写成
The author knocked off a book in less than a month.这位作者不到一个月就写出了一本书。
He knocked off 4000words before supper.他晚饭前就写了四千字。
He knocked a poem off impromptu at the meeting.他在会上即席写诗一首。
knock out（及物，可分）打倒，打昏
The short boxer knocked out his opponent in the fourth round.矮个子拳击运动员在第四个回合把他的对手击倒在地。
A blow on the head knocked him out.头上一记重击把他打昏了。
A brick fell on his head and knocked him out.一块砖掉在他头上，使他昏倒了。
knock up（及物，可分）匆忙做成
This book shelf is not too bad.I just knocked it up one weekend.这个书架还凑合，只不过是我用一个周末草草做成的。
He brought two of his friends home suddenly；I knocked up a meal for them.他突然带了两个朋友回家，我草草地为他们做了一顿饭。
knock...up（及物，必分）敲门［窗］叫醒
Knock me up at six tomorrow morning，please.请明天早上6点敲门叫醒我。
All of a sudden I was knocked up by my mother while sleeping soundly.我正熟睡着忽然被我母亲敲门叫醒。
knuckle down（不及物）努力工作起来
You must knuckle down from now on if you are determined to become an accomplished scholar.你如果立志要当有成就的学者，就必须从现在起努力工作。
He knuckled down to work as soon as he got back home.他一回到家里就专心致志地工作起来。