Grade 4 English noun worksheet with pluralization exercises and word sorting activity.

Let's solve the worksheet step by step.

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Part 1: Write the plural (if needed) of these words

We need to find the correct plural form for each word. Some words have irregular plurals, so we must be careful.

1. thesis → theses
*(Irregular plural – change 'is' to 'es')*

2. cirrus → cirri
*(Latin origin; plural is "cirri")*

3. fish → fish or fishes
*(Both are acceptable. "Fish" is used when referring to one type or general term; "fishes" refers to multiple species. But in most cases, "fish" is acceptable as plural.)*
✔ Answer: fish (commonly used plural)

4. step-uncle → step-uncles
*(Add -s to the end; compound noun with a noun part "uncle")*

5. observatory → observatories
*(Regular plural: add -ies after 'y' preceded by consonant)*

6. loaf → loaves
*(Irregular plural: change 'f' to 'v' and add -es)*

7. syllabus → syllabi or syllabuses
*(Latin origin; "syllabi" is more formal, but "syllabuses" is also accepted)*
✔ Common answer: syllabi

8. spotlight → spotlights
*(Regular plural: just add -s)*

9. agenda → agendas
*(Although it's Latin, modern English uses "agendas" as plural)*

10. most → most
*(This is an adjective or pronoun, not a noun. As a noun, "most" can be singular or plural depending on context, but it doesn't have a distinct plural form. So, it remains most.)*

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✔ Answers for Part 1:

1. theses
2. cirri
3. fish
4. step-uncles
5. observatories
6. loaves
7. syllabi
8. spotlights
9. agendas
10. most

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Part 2: Sort the words into Singular or Plural

List of words:
- tax
- atlases
- kiss
- life
- poppies
- leaves
- stitch
- arch
- wharf
- faxes
- emphases
- babies
- churches
- motto
- flushes
- brushes

Now, identify which are singular and which are plural:

#### Singular Words (only one item):
- tax
- kiss
- life
- stitch
- arch
- wharf
- motto

> Note: "tax", "kiss", "life", "stitch", "arch", "wharf", "motto" are all singular nouns.

#### Plural Words (already in plural form):
- atlases
- poppies
- leaves
- faxes
- emphases
- babies
- churches
- flushes
- brushes

> These all end in -s, -es, or have irregular forms like "churches".

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✔ Final Sorting:

Singular:
tax, kiss, life, stitch, arch, wharf, motto

Plural:
atlases, poppies, leaves, faxes, emphases, babies, churches, flushes, brushes

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✔ Complete Answer Key:

#### Part 1: Plural Forms
1. theses
2. cirri
3. fish
4. step-uncles
5. observatories
6. loaves
7. syllabi
8. spotlights
9. agendas
10. most

#### Part 2: Sorting

Singular Box:
tax, kiss, life, stitch, arch, wharf, motto

Plural Box:
atlases, poppies, leaves, faxes, emphases, babies, churches, flushes, brushes

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🔍 Explanation Summary:

- Regular plurals usually add -s or -es.
- Words ending in -us often become -i (e.g., *syllabus → syllabi*).
- Words ending in -f or -fe often change to -v + es (e.g., *loaf → loaves*).
- Some nouns are the same in singular and plural (like *fish*), others have irregular forms.
- Compound nouns like *step-uncle* follow regular plural rules: add -s to the main noun.
- Words like *most* can be tricky — they function as pronouns/adjectives, so they don’t typically take a plural form.

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