Educational worksheet for practicing comparative and superlative adjectives.

To solve this problem, we need to use the comparative and superlative forms of the adjectives provided in parentheses. Here's a step-by-step explanation for each sentence:

1. I am ________ than my sister. (TALL)

- The comparative form of "tall" is taller.
- Sentence: I am taller than my sister.

2. Russia is ________ country in the world. (BIG)

- The superlative form of "big" is biggest.
- Sentence: Russia is the biggest country in the world.

3. Susan’s hair is ________ than Maria’s hair. (LONG)

- The comparative form of "long" is longer.
- Sentence: Susan’s hair is longer than Maria’s hair.

4. Cars are ________ than bikes, but planes are ________. (FAST)

- The comparative form of "fast" is faster.
- The superlative form of "fast" is fastest.
- Sentence: Cars are faster than bikes, but planes are fastest.

5. My bike is ________ than my cousin’s bike. (NEW)

- The comparative form of "new" is newer.
- Sentence: My bike is newer than my cousin’s bike.

6. Thiago Eltes is ________ kid in my class. (YOUNG)

- The superlative form of "young" is youngest.
- Sentence: Thiago Eltes is the youngest kid in my class.

7. Mount Everest is ________ in the world. (HIGH)

- The superlative form of "high" is highest.
- Sentence: Mount Everest is the highest in the world.

8. An elephant is ________ than a dog. (HEAVY)

- The comparative form of "heavy" is heavier.
- Sentence: An elephant is heavier than a dog.

Final Answers:

1. taller
2. biggest
3. longer
4. faster, fastest
5. newer
6. youngest
7. highest
8. heavier

Boxed Final Answer:

\[
\boxed{
\begin{array}{l}
1. \text{taller} \\
2. \text{biggest} \\
3. \text{longer} \\
4. \text{faster}, \text{fastest} \\
5. \text{newer} \\
6. \text{youngest} \\
7. \text{highest} \\
8. \text{heavier}
\end{array}
}
\]