Prepare 6 Unit 15

Read each question carefully and choose the answer that best completes the sentence.

1. The explorers were lost at sea for weeks. They searched for an ________ for days, but all they saw was endless water.

2. The scientists were amazed by the ________ formations on the bottom of the lake. They had never seen anything like it before!

3. Last night, the sky was completely ________. It made it hard to see the stars.

4. The ________ was blowing so hard that it was difficult to walk. We had to hold onto each other for support.

5. As we climbed higher up the ________, the air grew colder and thinner.

6. The ________ was so deep that sunlight couldn't reach the bottom. It was a mysterious and dark place.

7. The ________ stretched for miles across the countryside. It was a beautiful sight to see.

8. The ________ was falling so heavily that it was hard to see anything beyond a few feet.

9. We _____ in the field all afternoon until it ______ to rain.

10. The strong wind _____across the ______ field, making it difficult to stand.

11. The researchers ______ data on the ______ river to learn more about its unique ecosystem.

12. The campers ______ a fire to stay warm as the temperature ________.