Comprehensive guide and practice sheet for students learning the rules of pluralizing nouns in English grammar.

Problem Overview:

The task is to write the plural form of each noun listed in the worksheet. The rules for forming plurals are provided at the top of the page, and we need to apply these rules to each noun.

Rules Recap:

1. Add "s":
- For most nouns: e.g., lamp → lamps.

2. Add "es":
- For nouns ending in s, x, ch, sh: e.g., class → classes.

3. Change "y" to "i" and add "es":
- For nouns ending in a consonant + y: e.g., city → cities.

4. Just add "s":
- For nouns ending in vowel + y: e.g., valley → valleys.

Solution:

We will go through each noun and apply the appropriate rule to form its plural.

---

#### a) window
- Rule: Add "s".
- Plural: windows

#### b) activity
- Rule: Add "s".
- Plural: activities

#### c) lunch
- Rule: Add "s".
- Plural: lunches

#### d) brush
- Rule: Add "es" (ends in "sh").
- Plural: brushes

#### e) monkey
- Rule: Change "y" to "i" and add "es" (ends in consonant + y).
- Plural: monkeys

#### f) bus
- Rule: Add "es" (ends in "s").
- Plural: buses

#### g) tax
- Rule: Add "es" (ends in "x").
- Plural: taxes

#### h) journey
- Rule: Change "y" to "i" and add "es" (ends in consonant + y).
- Plural: journeys

#### i) eye
- Rule: Add "s".
- Plural: eyes

#### j) library
- Rule: Add "s".
- Plural: libraries

#### k) holiday
- Rule: Add "s".
- Plural: holidays

#### l) six
- Rule: Irregular (no change).
- Plural: six

#### m) tray
- Rule: Change "y" to "i" and add "es" (ends in consonant + y).
- Plural: trays

#### n) beach
- Rule: Add "s".
- Plural: beaches

#### o) family
- Rule: Add "s".
- Plural: families

#### p) address
- Rule: Add "es" (ends in "s").
- Plural: addresses

#### q) dish
- Rule: Add "es" (ends in "sh").
- Plural: dishes

#### r) virus
- Rule: Add "es" (ends in "us").
- Plural: viruses

#### s) coach
- Rule: Add "es" (ends in "ch").
- Plural: coaches

#### t) island
- Rule: Add "s".
- Plural: islands

#### u) berry
- Rule: Add "s".
- Plural: berries

#### v) box
- Rule: Add "es" (ends in "x").
- Plural: boxes

#### w) branch
- Rule: Add "es" (ends in "ch").
- Plural: branches

#### x) eyelash
- Rule: Add "es" (ends in "sh").
- Plural: eyelashes

---

Final Answer:

```
a) windows
b) activities
c) lunches
d) brushes
e) monkeys
f) buses
g) taxes
h) journeys
i) eyes
j) libraries
k) holidays
l) six
m) trays
n) beaches
o) families
p) addresses
q) dishes
r) viruses
s) coaches
t) islands
u) berries
v) boxes
w) branches
x) eyelashes
```

Boxed Final Answer:
\boxed{
\begin{aligned}
&\text{a) windows} & &\text{b) activities} \\
&\text{c) lunches} & &\text{d) brushes} \\
&\text{e) monkeys} & &\text{f) buses} \\
&\text{g) taxes} & &\text{h) journeys} \\
&\text{i) eyes} & &\text{j) libraries} \\
&\text{k) holidays} & &\text{l) six} \\
&\text{m) trays} & &\text{n) beaches} \\
&\text{o) families} & &\text{p) addresses} \\
&\text{q) dishes} & &\text{r) viruses} \\
&\text{s) coaches} & &\text{t) islands} \\
&\text{u) berries} & &\text{v) boxes} \\
&\text{w) branches} & &\text{x) eyelashes}
\end{aligned}
}