let up . lessen in intensity；diminish；slacken off 减少；放松
It is raining hard as ever．It is not letting up at all．雨下得还是那么大，根本没有小下来。
Harry never lets up for a minute．哈利一刻也没有松劲。
let up . stop working 停止；停止做
Let up for a few minutes．You can't work hard all day．歇一会吧，你不能整天苦干。
The doctor has been working for fifty hours without letting up．医生已马不停蹄地连续工作了五十小时。
let up . become easier，kinder or less strict 宽容（常与on,连用）
Let up on Jane．She is sick．对简宽容点，她病了。
Let up on him．He didn't mean any harm．饶了他吧，他并没有什么恶意。
level down . make level by lowering the height of 铲平；弄平
That path is too high；level it down from here．那条路太高，从这里把它铲平。
level down . lower；reduce 降低；减低
We must make sure the expansion of higher education does not level down university standards．我们一定要做到既发展高等教育又不降低大学水平。
level off . make flat or level 整平；弄平
The bulldozers quickly levelled off the site．推土机很快就把工地平整了。
level off . even off；become steady 稳定；达到平衡
After going up for half a year，the cost of living levelled off in September．物价上涨了半年之后，在九月份稳定了。
Production has levelled off now and we don't expect to increase it ．现在生产已经稳定，我们并不期望增加生产。
level off . return to a horizontal position in flight（飞机）恢复水平飞行
The plane climbed to ten thousand metres and then levelled off．飞机升到一万米高度后就水平飞行了。
level out . move horizontally（after climbing）； remain steady（上升后）水平飞行；达到平衡
We climbed steeply after takeoff，and levelled out at twenty-five feet．我们起飞后就急剧上升，到达二万五千英尺时才水平飞行。
level out . remove by means of a lever 用杠杆移动
He levelled the stone out．他用杠杆挪动那块石头。
They have tried to level him out of his powerful position．他们试图把他从有权力的职务上拉下来。
level out . lift out 抬起
He levelled himself out of the chair．他从椅子上站起来。
level up . bring what is lower to an equality with what is higher 提升；提至高水平
The old clerks with small salaries applied to have them levelled up to the salaries of the newcomers．薪水低的老职员请求把他们的薪水提高到和新来的人一样高。
lie about . lie around . lie unused or unwanted 搁置不用
That old book was lying about for years before I finally threw it away．那本旧书搁放了好几年不用，最后我把它扔掉了。
lie about . lie around . be thrown about 到处乱放；乱撒
Don't leave your clothes lying about the room．不要把衣服乱扔在房间里。
lie about . lie around . lie idly doing nothing 闲躺着不干事
Don't lie about all day．别整天躺着啥事也不干。
lie back . get into or be in a lying position 躺下
Lie back，and you'll be more comfortable．向后靠，这样你会舒服些。
She lay back in bed．她仰着躺在床上。
lie back . stop working；rest 停止忙碌；休息
After a busy life he was content to lie back and take it easy．经过一生忙碌的生涯后，他对能休息下来享受清闲的生活而感到满足。
lie behind . be the cause of；be the explanation for 是…理由
I'm not sure what lay behind his remarks．我不清楚他说这样的话的原因是什么。
lie behind . have happened to；be in the past 先于…存在；已成过去
Some difficulties lie behind us，but greater ones lie ahead．有些困难已经过去，而更大的困难还在前面。
Behind lay nothing but defeat；ahead lay the certainty of victory．回顾过去，只有失败；展望未来，胜利在望。
lie down . recline 躺下
You had better go and lie down．你还是去躺一下好。
lie down . go to rest；sleep；wait 休息；睡觉；等候
I lay down for an hour．我躺下休息了一个小时。
Let me lie down；I am very tired．让我休息，我很疲倦。
lie down . fail in response to obligations；prove disappointing；purposely fail to do one's job 令人失望；有意失职；偷懒
He lay down on me．他令我失望。
If you lie down on your job，you will lose it ．你如果故意偷懒，就会失业。
Bell isn't trying to learn his lessons．He is lying down on the job．比尔不想学习，他是有意偷懒。
lie down . submit tamely；accept 驯服；接受；忍受
He lay down like a coward．他象懦夫一样地屈服了。
I hope you don't expect me just to lie down and take his insults．我想你不会要我容忍他的污辱的。
The men will not lie down under such treatment．工人们不会逆来顺受这种待遇。