keep 是一个常见的用来表示动作“保留”的单词，牢记它的固定搭配，保留该保留的。
Keep a diary (of) 记日记
I decided to keep a diary of our trip to Toronto.
我决定把我们去多伦多的旅行记下来。
Keep a promise 信守诺言
It is easier to make a promise than to keep a promise.
许下诺言比遵守诺言容易。
Keep a secret 保守秘密
Can I trust you to keep a secret?
我能相信你保守秘密吗？
解析：trust sb to do sth 表示信任某人做某事。
Keep calm 保持冷静
She has done her best to keep calm but finds herself trembling with tension and indecision.
她尽力保持镇定，可还是由于紧张、犹豫不决而抖个不停。
解析：find sb doing sth 表示发现某人在做某事，含有“进行”的意思，现在分词 trembling with tension and indecision 作补语，它与宾语 herself 有主动的关系。
Keep control (of) 保持控制
He was working hard to keep control of himself.
他正努力克制自己。
Keep in touch 保持联络
I keep in touch with a lot of my friends around the world.
我和世界各地的许多朋友保持联系。
解析：lots of 和 a lot of 意思一样，意为“许多”，表示量很大，但是没必要指明量的多少，多用在比较不正式的谈话或是写作中（正式的用 many 或 much），后面跟可数名词和不可数名词，谓语的单复数根据后面接的名词来变化。
Keep quiet 保持安静
The only thing I can do is to keep quiet and sit this one out.
我唯一能做的就是保持沉默，等待这件事结束。
解析：不定式短语 to keep quiet and sit this one out 在句中作表语。
Keep records 做好记录
It's usual to keep records of all expenses.
通常要把所有费用都记下来。
Keep score 记分
Could you keep score at this afternoon's match?
你能不能为今天下午的比赛记分？
Keep someone's place 保留某人的位置
Would you mind keeping my place for a minute?
你能帮我留一会儿吗？
Keep the change 不用找零钱了
I told the taxi driver to keep the change.
我告诉出租车司机不用找零钱了。
Keep your balance 保持平衡
You must learn to keep your balance in skating.
你必须学会在滑冰时保持平衡。