III. Chọn từ hoặc cụm từ thích hợp nhất để điền vào chỗ trống trong mỗi câu sau. Viết A, B, C hoặc D vào phiếu trả lời của bạn.

1. I never forget the time I saw A. a UFO.

2. I think life won't be boring C. on Mars.

3. Astronauts stay in a B. space station when they are in space.

4. People sometimes call B. Mars the Red Planet.

5. It will be D. enough difficult to get food on space stations without a reliable way to grow food in space.

6. Temperature in Venus is much B. hotter than it on Earth.

7. The flying saucer was making a strange noise C. as it came down.

8. Tom is talking to Peter.

Tom: "I was playing soccer when I saw two very strange people in the park. They were walking towards me. They were green and they were very tall."

-Peter: B. That sounds scary. Who do you think they were?  

1. UFO A. stands for Unidentified Flying Object.

2. The temperature in the Arctic can fall B. below zero degrees Celsius in winter.