(
B
) 6. Why do many countries want to send astronauts to Mars?
A. Because spacecraft couldn't work on Mars.
B. Because humans could work faster and smarter than machines.
C. Because scientists have worked out how to survive on Mars.
D. Because space travel is always free of danger for astronauts.
(
C
) 7. How long would it take astronauts to reach Mars?
A. A few days.
B. At least six weeks.
C. At least six months.
D. Less than half a year.
(
B
) 8. According to the passage, which of the following is TRUE?
A. A trip to the Moon would be the farthest journey in human history.
B. Space radiation might raise the risk of health problems for astronauts.
C. Taking certain vitamins can help reduce pressure behind the eyes in space.
D. Astronauts don't have to pack light to lift off from the Earth in the last 60 years.
(
C
) 9. In the last paragraph, the writer implies(暗示) that ______.
A. Mars astronauts will be able to get things they need
B. Mars astronauts can grow lettuce and other food now
C. 3-D printing techniques could allow astronauts to build tools as needed
D. astronauts could develop 3-D printing techniques on Mars in the future
(
A
) 10. The passage is mainly about ______.
A. surviving a trip to Mars
B. spacecraft landing on Mars
C. health problems of astronauts
D. dangers of getting to Mars
