keep 是一個常見的用來表示動作「保留」的單詞，牢記它的固定搭配，保留該保留的。
Keep a diary (of) 記日記
I decided to keep a diary of our trip to Toronto.
我決定把我們去多倫多的旅行記下來。
Keep a promise 信守諾言
It is easier to make a promise than to keep a promise.
許下諾言比遵守諾言容易。
Keep a secret 保守秘密
Can I trust you to keep a secret?
我能相信你保守秘密嗎？
解析：trust sb to do sth 表示信任某人做某事。
Keep calm 保持冷靜
She has done her best to keep calm but finds herself trembling with tension and indecision.
她盡力保持鎮定，可還是由於緊張、猶豫不決而抖個不停。
解析：find sb doing sth 表示發現某人在做某事，含有「進行」的意思，現在分詞 trembling with tension and indecision 作補語，它與賓語 herself 有主動的關係。
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 保持聯絡
I keep in touch with a lot of my friends around the world.
我和世界各地的許多朋友保持聯繫。
解析：lots of 和 a lot of 意思一樣，意為「許多」，表示量很大，但是沒必要指明量的多少，多用在比較不正式的談話或是寫作中（正式的用 many 或 much），後面跟可數名詞和不可數名詞，謂語的單複數根據後面接的名詞來變化。
Keep quiet 保持安靜
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，等待這件事結束。
解析：不定式短語 to keep quiet and sit this one out 在句中作表語。
Keep records 做好記錄
It's usual to keep records of all expenses.
通常要把所有費用都記下來。
Keep score 記分
Could you keep score at this afternoon's match?
你能不能為今天下午的比賽記分？
Keep someone's place 保留某人的位置
Would you mind keeping my place for a minute?
你能幫我留一會兒嗎？
Keep the change 不用找零錢了
I told the taxi driver to keep the change.
我告訴計程車司機不用找零錢了。
Keep your balance 保持平衡
You must learn to keep your balance in skating.
你必須學會在滑冰時保持平衡。