Tracking StationsOne night in February 1962, John H. Glenn, Jr., flew over Australia. The

Tracking Stations
One night in February 1962, John H. Glenn, Jr., flew over Australia. The man in the Mercury（水星）capsule（宇宙飞行容器）was alone, but friendly voices reached him by radio. Over the dark land 100 miles below, he saw sparkling lights. It marked the city of Perth, where people had turned on their lights as a greeting to him.
In Friendship 7, Glenn radioed, the lights show up very well. Thank everybody for turning them on. His capsule needed on to the east.
During his three orbits of the earth, Glenn could always reach one of the eighteen tracking stations. Some of them were on ships at sea. Others were in the United States.
Many of the stations had been built with the help of other countries. These countries allowed Americans to bring in radio equipment and set it up. Without the help of such lands as Nigeria, Zanzibar, and Mexico, there would have been breaks in the worldwide radio network. John Glenn, Jr., was the first American to orbit the earth. For his flight, the tracking network（跟踪网络）covered 60,000 land or statute miles（法定英里）. Five hundred men worked in the stations along the route. Since his flight, the network has grown. Today, it covers more than 100, 000 statute or land miles and has about one hundred stations. One-third of these stations are outside the United States.
66．This passage is mainly about .
A．talking to ships at sea around the world
B．breaks in the worldwide network
C．the first American to orbit the earth
D．a satellite which fell into the ocean
67．From the passage we can see that .
A．Friendship 7 stopped in Perth, Australia
B．all tracking stations are inside the United States
C．radio equipment is important in space flight
D．many people could see Glenn in his capsule when he made the flight
68．During his flight Glenn could always .
A．see lights turned on the ground B．reach ships at sea
C．reach one of the tracking stations D．arrive at Mercury in his Friendship 7
69．Why did people in Perth turn on the lights?
A．They wanted to guide him to land.
B．It was too dark for them to see in the room.
C．They wanted to see the Friendship 7．
D．They wanted to greet Glenn.
70．Which of the following is NOT true?
A．Countries must work together to track satellites.
B．There are now about 30 tracking stations outside the United States.
C．The tracking network covers many more statute miles now than before.
D．Nobody has orbited the earth except Glenn.66-70 CCCDD

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这个解释是对的