The word “they” in paragraph 1 refers to ______.

* Hướng dẫn giải

Dẫn chứng: tropical cyclones are huge rotating storms 200 to 2,000 kilometers wide with winds that blow at speeds of more than 100 kilometers per hour (kph). Weather professionals know them as tropical cyclones, but they are called hurricanes in the Caribbean Sea, typhoons in the Pacific Ocean, and cyclones in the Indian Ocean.