（）发起，发动

A.拥抱

B.发动

C.激活

D.升级

The American Space Agency ______ (delay)the launch of the Shuttle Endeavour while it tries to find out what damage ______ (do)by 11 lightening strikes around the launch pad at Cape Canaveral.

A.abel

B.uxury

C.aser

D.aunch

？

A.成立于1975年

B.由十国集团中央银行行长发动成立

C.旨在维护国际银行体系稳定

D.中国是发起国之一

ssion. Francis R. (Dick) Scobee was the mission commander. The crew included Christa McAuliffe, a high-school teacher from New Hampshire. The five other crew members were Gregory B. Jarvis, Ronald E. McNair, Ellison S. Onizuka, Judith A. Resnik, and Michael J. Smith.

After several launch delays, NASA officials overruled the concerns of engineers and ordered a liftoff on a cold morning, Jan. 28, 1986. The mission ended in tragedy. Challenger disintegrated into a ball of fire. The accident occurred 73 seconds into flight, at an altitude of 14020 meters and at about twice the speed of sound.

Strictly speaking, Challenger did not explode. Instead, various structural failures caused the spacecraft to break apart. Although Challenger disintegrated almost without warning, the crew may have briefly been aware that something was wrong. The crew cabin tore loose from the rest of the shuttle and soared through the air. It took almost three minutes for the cabin to fall to the Atlantic Ocean, where it smashed on impact, killing the seven crew members.

All shuttle missions were halted while a special commission appointed by President Reagan determined the cause of the accident and what could be done to prevent such disasters from happening again. In June I986, the commission reported that the accident was caused by a failure of O rings in the shuttle's right solid rocket booster. These rubber rings sealed the joint between the two lower segments of the booster. Design flaws in the joint and unusually cold weather during launch caused the O rings to allow hot gases to leak out of the booster through the joint. Flames from within the booster streamed past the failed seal and quickly expanded the small hole. The flaming gases then burned a hole in the shuttle's external fuel tank. The flames also cut away one of the supporting beams that held the booster to the side of the external tank. The booster tore loose and ruptured the tank. The propellants (火箭燃料) from the tank formed a giant fireball as structural failures tore the vehicle apart.

The commission said NASA's decision to launch the shuttle was flawed. Top-level decision makers had not been informed of problems with the joints and O rings or of the possible damaging effects of cold weather.

Shuttle designers made several technical modifications, including an improved O-ring design and the addition of a crew bail-out system. Although such a system would not work in all cases, it could save the lives of shuttle crew members in some situations. Procedural changes included stricter safety reviews and more restrictive launching conditions. The space shuttle resumed flying on Sept.29, 1988, with the launch of the redesigned shuttle Discovery. (465 words)

The word "overrule" in the first sentence of paragraph 2 means ______.

A．share

B．ignore

C．consider

D．know

A.发起主动攻击的机器

B. 被黑客植入木马的机器，黑客通过木马控制端控制肉鸡参与攻击

C. 用户通常自愿成为肉鸡

D. 肉鸡不能发动攻击

A.发起主动攻击的机器

B. 被黑客植入木马的机器,黑客通过木马控制端控制肉鸡参与攻击

C. 用户通常自愿成为肉鸡

D. 肉鸡不能发动攻击