重點講解：
1. reference to
提及；談到；有關；
eg. He made no reference to any agreement.
他沒有提到什么協議。
eg. I am writing with reference to your job application.
敬覆者，關于您申請工作一事。
2. come from
來自；始于；
eg. Nearly half the students come from abroad.
將近一半的學生來自國外。
eg. Chocolate comes from the cacao tree.
巧克力出自可可樹。
eg. The term 'claret', used to describe Bordeaux wines, may come from the French word 'clairet'.
用來指稱波爾多葡萄酒的詞 claret 可能源于法語單詞 clairet。
3. stand for
代表，表示；
eg. What does EU stand for?
EU代表什么？
eg. The letter "x" is often used to stand for an unknown number.
字母x常被用來代表一個未知數。