题目内容：

    On Thursday morning, two teenage boys were rescued by a drone (无人机) in Australia while lifeguards were still training to use the machine.

The ______, aged 15-17, got into difficulties about 700 feet off the coast of Lennox Head, New South Wales (NSW). A passerby saw them ______ in dangerous waves. Lifesavers ______ sent the drone to drop a lifeboat, and the pair made their way safely to the ______.

The drone, known as “Little Pipper”, was actually not ______ to be saving anyone just yet---lifeguards were being trained to ______ the machine. When a call came about the swimmers ______, the drone happened to be nearby.

Jai Sheridan was the lifeguard who ______ the drone. He described the experience as ______. “The Little Ripper ______ proved itself today. It is a highly efficient (高效的) piece of lifesaving equipment. I was ______ the drone when the alarm was raised. I directed it towards the swimmers, and dropped the ______. With its support they made their way to safety. They were ______, but not hurt. The teens were rescued in just 70 seconds with the drone---while a lifeguard would have taken up to six minutes to ______ the rescue.”

John Barilaro, an official of the state, ______ the rescue as historic. “It was the world’s ______ rescue by the unmanned aircraft”, he said. “Never before has a drone been used to ______ swimmers like this.”

Last December, the NSW state government ______ some “Little Ripper” drones for 247,000 pounds. ______ some are designed to spot sharks, others are ______ with lifeboats, alarms and loudspeakers. “It was money well spent,” said John Barilaro.

1.A. swimmers B. pilots C. visitors D. rescuers

2.A. playing B. surfing C. struggling D. training

3.A. finally B. secretly C. immediately D. gratefully

4.A. island B. ship C. hospital D. shore

5.A. advised B. supposed C. allowed D. guided

6.A. operate B. repair C. work D. power

7.A. in charge B. in place C. in action D. in trouble

8.A. flew B. brought C. checked D. designed

9.A. funny B. useful C. amazing D. important

10.A. necessarily B. basically C. probably D. certainly

11.A. studying B. piloting C. boarding D. inspecting

12.A. lifebelt B. lifeline C. lifeguard D. lifeboat

13.A. sick B. tired C. excited D. surprised

14.A. record B. complete C. experience D. report

15.A. thanked B. greeted C. imagined D. praised

16.A. latest B. best C. first D. quickest

17.A. rescue B. warn C. protect D. reward

18.A. offered B. bought C. booked D. made

19.A. Since B. Unless C. While D. Before

20.A. equipped B. connected C. covered D. filled