English vocabulary learning worksheet with images and words for children to practice using "a" and "an."

Task Explanation:

The task involves filling in the blanks with either "a" or "an" before each noun. The choice between "a" and "an" depends on the sound that begins the following word:
- Use "a" before words that start with a consonant sound.
- Use "an" before words that start with a vowel sound (a, e, i, o, u).

Solution:

Let's go through each item and determine whether to use "a" or "an":

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#### 1–12:
1. orange: Starts with a vowel sound → an orange
2. apple: Starts with a consonant sound → an apple
3. umbrella: Starts with a consonant sound → an umbrella
4. rabbit: Starts with a consonant sound → a rabbit
5. bus: Starts with a consonant sound → a bus
6. university: Starts with a vowel sound → a university
7. desk: Starts with a consonant sound → a desk
8. elephant: Starts with a consonant sound → an elephant
9. sheep: Starts with a consonant sound → a sheep
10. lemon: Starts with a consonant sound → a lemon
11. egg: Starts with a vowel sound → an egg
12. uniform: Starts with a consonant sound → a uniform

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#### 13–24:
13. igloo: Starts with a vowel sound → an igloo
14. giraffe: Starts with a consonant sound → a giraffe
15. banana: Starts with a consonant sound → a banana
16. uncle: Starts with a consonant sound → an uncle
17. flower: Starts with a consonant sound → a flower
18. ear: Starts with a vowel sound → an ear
19. bear: Starts with a consonant sound → a bear
20. ring: Starts with a consonant sound → a ring
21. arm: Starts with a consonant sound → an arm
22. farmer: Starts with a consonant sound → a farmer
23. eye: Starts with a vowel sound → an eye
24. eraser: Starts with a consonant sound → an eraser

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Final Answer:

Here is the completed list:

1. an orange
2. an apple
3. an umbrella
4. a rabbit
5. a bus
6. a university
7. a desk
8. an elephant
9. a sheep
10. a lemon
11. an egg
12. a uniform
13. an igloo
14. a giraffe
15. a banana
16. an uncle
17. a flower
18. an ear
19. a bear
20. a ring
21. an arm
22. a farmer
23. an eye
24. an eraser

Final Answer Boxed:
\[
\boxed{
\text{an orange, an apple, an umbrella, a rabbit, a bus, a university, a desk, an elephant, a sheep, a lemon, an egg, a uniform, an igloo, a giraffe, a banana, an uncle, a flower, an ear, a bear, a ring, an arm, a farmer, an eye, an eraser}
}
\]