1. Don't work too late. Go home and take some break.不要工作太晚，回家休息吧!
2. The new key doesn't suit the lock.新鑰匙無法開鎖。
3. We have learned a lot of knowledge from this professor.我們從這位教授身上學到很多知識。
4. I have been finding for my wallet all morning! 我整個早上都在找我的皮夾。
5. Did you accept the letter I sent you yesterday?你收到我昨天寄給你的信了嗎?

Debug Answer: 

1. Don't work too late. Go home and take some rest.
   break 是活動暫停的休息，例如午休；rest 是指完全不做事的休息。本句是指回休息，所以用 rest.
2. The new key doesn't fit the lock.
   suit 和 fit 都有適合的含意。但suit 指條件、場合、身分、時間等的合適，fit 則重於大小合適。這個句子裡鑰匙無法開鎖，必須用 fit 來代表鑰匙和鎖的不合適。
3. We have gained a lot of knowledge from this professor.
   雖然中文可以說學到知識，在英文中knowledge 不是用學來的，需要用有 " 到，獲得 " 意思的動詞，例如:get, gain, acquire
4. I have been looking for my wallet all morning!
   find 和 look for 都是尋找，但是 find 著重在結果，代表找到了，look for 則是著尋找的過程。本句用完成進行式，必須用 look for 來表示尋找動作的持續。
5. Did you receive the letter I sent you yesterday? 
   accept 是強調主動地接受，有同意的意味；receive 則是指被動的收到。因此收邀請要用 accept an invitation，收到電子郵件則用receive an email.