四六级考试

【单选题】Mars fascinates scientists because of its similarity toEarth, and it fascinates the public because our myth of "Martians" is a vision of life beyondEarth. The Mars 62 continues with the launch of a robot vehicle by UK scientists. It’s part of a project to build an "autonomous robotic scientist" to 63 the Martian surface and is key to theEuropean SpaceAgency’s 2011ExoMars 64 .
The six-wheeled vehicle housing a myriad of scientific 65 and detectors is the Mars rover, nicknamed "Bridget".Astrium, anEADS company, are 66 theExoMars rover prototype and coordinating its 67 with other UK-based institutions.
Searching for a 68 similar to that found on Mars, the team took the rover toEl Teide National Park in Tenerife. Lester Waugh, leading theEADSAstrium team, explains, "The rover’s not waterproof so the conditions need to be dry as any moisture affects the way the sand 69 under the wheels."
Solar panels will supply power and radioisotope(放射性同位素 ) heater units will help it withstand the cold on Mars. The team is optimizing the performance of the wheels, suspension, the drive system, 70 it doesn’t dig itself in on tricky terrain.
Taking 71 to twenty minutes for radio signals to reachEarth demands a powerful 72 system to allow the rover to operate 73 so they are also developing next generation computer software 74 .
The rover will land on Mars packed to capacity 75 scientific gadgets designed to be as light and as small as possible. The 76 development time is essential for rigorous testing, as Waugh explains," 77 we put things in space we have to make sure that they’ll 78 the radiation environment, the 79 of heat and colD、Our science 80 is crucial, and malfunctions may affect that. The more science we get back the better 81 there is for spending more money on planetary exploration.\
A．Before
B．After
C．When
D．If

网考网参考答案：C
网考网解析：
[一点即通] 语义衔接题。本处意思是：当我们向太空发射探测器时…。C when“当…时”。 [避错指导] before，after，if均不符合上下文语义。 document.getElementById("warp").style.display="none"; document.getElementById("content").style.display="block"; 查看试题解析出处>>