Variant 1 You could have come first and won the race if you … faster

21. Why do helicopters not need runways ...

A) they are smaller than planes. B) they can fly backward.

C) they can take off without moving forward. D) they can hover in the air.

22. What does the word CONVENTIONAL in the text refer …

A) delete B) tradition C) created for the first time D) for a large group of people

23. How are helicopters used as ambulances?

A) They lift trees out of forests. B) They airlift people uot of accident.

C) They chase suspects on the ground. D) They can drop water on fires.