问题详情

Questions 16 to 18 are based on the passage you have just heard.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.
18.
A.They are extremely accurate.
B.They were first made in space.
C.They are expensive to make.
D.They were invented in the 1970s.
17.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.请帮忙给出每个问题的正确答案和分析，谢谢！