keep the balance of nature 保持生態平衡
It is important that we ( should ) keep the balance of nature.
keep/stay awake 保持醒著
He tried to keep awake.
keep a diary 記日記
His father ordered that he should keep a diary in English.
keep healthy/fit 保持身體健康
Keep healthy first if you want to become wealthy.
keep one’s temper 不發脾氣
You should learn to keep your temper under control.
keep sb. informed of sth. 讓某人了解某事
He will keep the RO informed of any incidents.
Keep sb. from doing sth. 阻止某人做某事
These days it may keep you from losing your cool.
Keep in touch with 保持聯系
We must keep in touch with each other.
keep doing something 一直做某事
He keeps running in the morning everyday.
keep / bear / have sth in mind 心里想著某事
Keep it in mind . Please don't forget.
keep one’s promise 遵守諾言
One should keep his promise.
keep back 扣下，*隱瞞，*留在后面
She was unable to keep back her tears, and wept freely.
He couldn't keep down his anger.
keep up 保持
We are very anxious to keep up the reputation of the firm.
keep up with 跟上，*及時了解
The child could not keep up with his father's strides.
keep watch 執勤，*警惕
Who will keep watch tonight?
keep out of 不惹事
Tell the children to keep out of mischief!
keep an eye out for sb/sth 留人或注意某人或某事物
Keep an eye out for anyone selling tickets.
keep an eye on 照料，*照管
Will you please keep an eye on my luggage?
knock at 敲門
He knock at the door and enter.
kinds of 各種各樣的
You can avoid all kinds of trouble by letting well alone.
Kneel down 下跪
Christians often kneel down to say their prayers.
Knock down 撞到，*搶劫
He wanted to knock down a bank.
knock over 打翻,*偷竊,*使吃驚,*輕易擊敗
Look out! Don't knock the stool over.
knock into sb. 撞倒某人身上，*遇見
I was so hurried as to knock into my teacher.
knock against 撞到…上
He advanced with precaution, taking care not to knock against the furniture.
knock up 敲門叫某人起床
Except for the persons she had gone to knock up, everyone was present.
knock off 停止工作，*降低
Let's knock off now.
This little lady will knock out a tank at 300 yards.
know about 了解……情況
Keep quiet, we don't want the whole world to know about it.
know of 聽說過
I don't know the writer, but I know of him.