What are homogeneous members?
A sentence is built from parts such as the subject (who or what), the predicate (what is done), and describing or adding words. Sometimes two or more words do the same job and answer the same question. These are homogeneous members. The word homogeneous means of the same kind.
Example: She bought apples, pears and figs. All three words answer the question what? and all three depend on the same word, bought. They can be subjects (Girls and boys came), predicates (She sang and danced), objects, describing words, or adverbs (He spoke slowly and clearly).
Rule of thumb: same question + same job = homogeneous.
Linking equal words: with and without conjunctions
There are three ways to link equal members.
- No conjunction: use commas only. Apples, pears, figs. You can feel the voice rise and pause at each comma.
- One conjunction (and, or): commas between the earlier words, but no comma before the single and. Apples, pears and figs. Some writers add a comma before and (the serial or Oxford comma): it is allowed, but be consistent.
- Repeated conjunction (and ... and ...): in English no commas are needed: apples and pears and figs. Some languages, such as Ukrainian, put a comma before every repeated conjunction, so check the rule of your own language.
Several rows. A sentence can hold more than one row of equal members: Girls, boys and kids sing, dance and play. Here the subjects form one row and the predicates form a second row. Each row follows the comma rules on its own.
Joining, contrasting and dividing relations
The link word tells us how the equal members are related.
- Joining (and, as well as): both belong together. She reads and writes. No comma before and.
- Contrasting (but, yet, although): the second goes against the first. He is small, but strong. A comma goes before but.
- Dividing (or, either ... or): a choice, one at a time. Tea or coffee? No comma before a single or.
Careful: and can also join two whole clauses (The sun rose, and the birds sang). That is a different rule. In this lesson we look only at equal members inside one clause.
Homogeneous and non-homogeneous describing words
Two describing words (attributes) before a noun are not always equal.
- Equal (homogeneous): each word describes the noun on its own and in the same way. A tall, strong boy. You can put and between them or swap them.
- Not equal (non-homogeneous): the second word is tied closely to the noun and forms one idea with it. The first word describes that idea. A famous Italian singer, a big red balloon, an old wooden table. No comma.
The and test: say tall and strong boy. It sounds right, so use a comma. Say famous and Italian singer. It sounds wrong, so no comma. Second test: swap the words. Strong, tall boy is fine; Italian famous singer is not.
Generalising words: colon and dash
A generalising word names the whole group that the equal members belong to. Examples: fruit, everyone, all, everywhere, all of these.
- Generalising word first: put a colon after it. She bought fruit: apples, pears and figs.
- Generalising word after the list: put a dash before it. Apples, pears and figs โ all of these are fruit.
If the list sits in the middle of a sentence, dashes can wrap it on both sides: Everything โ pens, books, bags โ was packed. Never put a colon right after a verb or after a preposition that needs the list to finish the thought: write She bought apples, pears and figs, not She bought: apples, pears and figs.
Typical errors in sentences with homogeneous members
- Mixed style. Using the serial comma in one list (apples, pears, and figs) and leaving it out in the next. Pick one style and keep it.
- Missing comma without a conjunction. Wrong: apples pears figs.
- Comma between the subject and predicate. Wrong: The boys, ran.
- Comma between non-equal describing words. Wrong: a famous, Italian singer.
- Mixing kinds. Wrong: She likes dancing, music and to swim. Keep the same form: dancing, music and swimming.
- Colon after a verb. Wrong: I need: pens and paper.
Try it
Predict, then check. Open the 3D and go to step 4. For each pair, say aloud: tall and strong boy. Does it sound right? Decide, then press the button to check.
At home. Write your family's shopping list in one sentence with commas and and. Then add a generalising word and a colon: We need groceries: rice, milk and eggs. Swap it round with a dash: Rice, milk and eggs โ all of these are groceries.
Key formulas and definitions
- Equal members = same question + same job in the sentence
- A, B and C โ commas between the earlier words, no comma before the single and
- A and B and C โ no commas in English (check the rule of your language)
- A, but B โ comma before but (contrast)
- General word: A, B, C โ colon after the general word; dash before it if it comes last
- And test: tall and strong boy? yes โ comma; famous and Italian singer? no โ no comma
Worked examples
1. Find the homogeneous members: The tailor measured, cut and stitched the cloth.
The predicates measured, cut and stitched all answer what did the tailor do? and share the subject tailor. They are equal members. Commas separate the first two; and joins the last.
2. Punctuate: We visited Delhi Agra and Jaipur.
Delhi, Agra and Jaipur answer the same question (which places?). Use a comma between the earlier words and no comma before the single and: We visited Delhi, Agra and Jaipur.
3. Does a comma go in a cold rainy morning?
Apply the and test: cold and rainy morning sounds fine, and the words can swap. They are equal, so: a cold, rainy morning.
4. Does a comma go in an old wooden table?
Old and wooden table sounds odd. Wooden table is one idea; old describes it. They are not equal, so no comma: an old wooden table.
5. Punctuate with a generalising word: Pens pencils rulers all these are stationery.
The generalising word all these comes after the list, so a dash goes before it: Pens, pencils and rulers โ all of these are stationery.
6. Find the two rows: Teachers and students read and discuss.
Row 1 (subjects): teachers and students. Row 2 (predicates): read and discuss. There is a single and in each row, so no commas are needed.
7. Punctuate: He tried hard but failed.
But shows contrast, so a comma goes before it: He tried hard, but failed.
Common mistakes
- Putting a comma between non-equal describing words, such as a famous, Italian singer.
- Forgetting commas when no conjunction is used: apples pears figs.
- Writing a colon straight after a verb: I need: pens and paper.
- Using a comma between a subject and its predicate: The boys, ran.