[单项选择]More than a year has passed since the space shuttle Columbia broke into pieces over central Texas. This past January President Bush announced a long-term program of space exploration that would return human beings to the Moon, and thereafter send them to Mars and beyond. As this magazine (Natural History) goes to press, the twin Mars Exploration Rovers, Spirit and Opportunity, are wowing the scientists and engineers at the rovers’ birthplace--NASA’s Jet Propulsion Laboratory (JPL)--with their skills as robotic field geologists. JPL’s official rover Web site is being stampeded by visitors. The confluence of these and other events resurrects a perennial debate: with two shuttle failures out of 112 missions, and the astronomical expense of the manned space program, can sending people into space be justified, or should robots do the job alone
Modern societies have been sending robots into space since 1957, and people since 1961. Fact is, it’s vastly cheaper to send robots: in most cas
A. A．1) most probably means ______ . hacked severelyB. clicked frequentlyC. closed foreverD. neglected purposely

[单项选择]More than a year has passed since the space shuttle Columbia broke into pieces over central Texas. This past January President Bush announced a long-term program of space exploration that would return human beings to the Moon, and thereafter send them to Mars and beyond. As this magazine (Natural History) goes to press, the twin Mars Exploration Rovers, Spirit and Opportunity, are wowing the scientists and engineers at the rovers’ birthplace--NASA’s Jet Propulsion Laboratory (JPL)--with their skills as robotic field geologists. JPL’s official rover Web site is being stampeded by visitors. The confluence of these and other events resurrects a perennial debate: with two shuttle failures out of 112 missions, and the astronomical expense of the manned space program, can sending people into space be justified, or should robots do the job alone
Modern societies have been sending robots into space since 1957, and people since 1961. Fact is, it’s vastly cheaper to send robots: in most cas
A. The high expense of the manned space program.
B. The inefficient work of Jet Propulsion Laboratory.
C. The heavy casualties in the space shuffle wreckage.
D. The announcement of a long-term space exploration.

[单项选择]Passage Five