Đáp án đúng là B

Script:

Good morning, everyone. Today I'd like to tell you about life on a planet called Planet Hope.

Planet Hope is in the Milky Way Galaxy. It is three times bigger than Earth. It has three suns and four moons, so the weather is hot all year round, and its surface is quite dry. Planet Hope has only one season.

The creatures living there are Hopeans, and they don't look like us. They have a big head, four eyes, two legs, and four arms. They have thick skin to protect them from the heat. They are very friendly and hospitable. They are only dangerous to people who try to attack them.

Hopeans grow special plants for food. They don't drink liquid water, they drink a type of petrol from under the ground. Hopeans use rockets to travel at very high speeds.

That is my description of Planet Hope and the creatures living on it. I hope you enjoyed it and thank you for listening.

Someone _________ at the door. Can you hear it? A. knocks B. is knocking C. will knock D. was knocking