单项选择题

Questions 16 to 18 are based on the passage you have just heard.
18题选（）.

A.They are extremely accurate
C.They were first made in space
B.They are expensive to make
D.They were invented in the 1970s

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热门试题

单项选择题17题选（）.

A.They accurately calculated the speed of the orbiting shuttles
B.They developed objects for astronauts to use in outer space
C.They tried to meet astronauts' specific requirements
D.They tried to make best use of the latest technology

单项选择题16题选（）.

A.When America's earliest space program started
B.When the International Space Station was built
C.How many space shuttle missions there will be
D.How space research benefits people on Earth

Questions 16 to 18 are based on the passage you have just heard. 18题选（）.

Questions 16 to 18 are based on the passage you have just heard.
18题选（）.