1. clothes, cloth, clothing
clothes统指各种衣服，谓语动词永远是复数， cloth指布，为不可数名词 clothing 服装的总称，指一件衣服用a piece of, an article of
2. incident, accident
incident指小事件, accident指不幸的事故He was killed in the accident.
3. amount, number
amount后接不可数名词， number后接可数名词 a number of students
4. family, house, home
home 家，包括住处和家人，house房子，住宅，family家庭成员. My family is a happy one.
5. sound, voice, noise
sound自然界各种各样的声音，voice人的嗓音，noise噪音I hate the loud noise outside.
6. photo, picture, drawing
photo用照相机拍摄的照片，picture可指相片，图片，电影片，drawing画的画 Let's go and see a good picture.
7. vocabulary, word
vocabulary词汇，一个人拥有的单词量，word具体的单词He has a large vocabulary.
8. population, people
population人口，人数，people具体的人 China has a large population.
9. weather, climate
weather一天内具体的天气状况，climate长期的气候状况 The climate here is not good for you.
10. road, street, path, way
road具体的公路，马路，street街道，path小路，小径，way道路，途径
take this road; in the street, show me the way to the museum.
11. course, subject
course课程（可包括多门科目），subject科目（具体的学科）a summer course
12. custom, habit
custom传统风俗，习俗，也可指生活习惯，后接to do， habit生活习惯，习惯成自然，后接of doing. I've got the habit of drinking a lot.
13. cause, reason
cause 指造成某一事实或现象的直接原因，后接of sth./doing sth，reason用来解释某种现象或结果的理由，后接for sth./doing sth. the reason for being late
14. exercise, exercises, practice
exercise运动，锻炼（不可数），exercises练习（可数），practice（反复做的）练习 Practice makes perfect.
15. class, lesson
作"课"解时,两者可以替换.指课文用lesson. 指班级或全体学生用class. lesson 6; class 5
16. speech, talk, lecture
speech指在公共场所所做的经过准备的较正式的演说，talk日常生活中的一般的谈话，讲话，lecture学术性的演讲，讲课 a series of lecture on…
17. officer, official
officer部队的军官，official政府官员 an army officer
18. work, job
二者均指工作。work不可数，job可数 a good job
19. couple, pair
couple主要指人或动物，pair多指由两部分组成的东西 a pair of trousers
20. country, nation, state, land
country侧重指版图，疆域，nation指人民，国民，民族，state侧重指政府，政体，land国土，国家 The whole nation was sad at the news.
