46 What is the main reason for NIST to develop the new elevators?
(A) To secure better cooperation with their colleagues from around the world.
(B) To relieve firefighters of elevator operation duties in a fire emergency.
(C) To improve their research in technology by working with the elevator industry.
(D) To use elevators for rescue and evacuation purposes in a fire safely and effectively.

The elevators are the primary最重要的, 首要 means of vertical豎直的；垂直的 transportation in most high-rise buildings and potentially潛在地；可能地 can play a vital關鍵 role in the event of an emergency, such as a fire.

The dominant主要的；主導的；佔優勢 practice around the world, however, is to discourage the use of elevators during a fire. The major reason for this practice is the unpredictability不可預測性;不可預知性 of the condition狀態, 狀況 of the emergency and the danger of entrapping裹住;積留;捕集;收集 passengers as well as和… rescue workers (e.g. firefighters) in the elevator.  

      To safeguard the use of elevators in a fire emergency, the US National Institute of Standard and Technology (NIST) is working with the elevator industry to develop new elevators that function during fires. The new elevators are designed to be used both as a rescue vehicle, carrying firefighters to the site地點 of the blaze熊熊燃燒、大火, and as a secondary method (after stairwells（建築物內的）樓梯井) for evacuating building occupants居住者, 佔有人.

NIST is investigating software and sensing systems that can adapt to changing smoke and heat conditions so that the elevators can maintain safe and reliable operation during fire emergencies. Such changes could also allow elevators to be operated with remote control from the ground floor during fires, thus freeing urgently緊急地 needed firefighters from elevator operation duties.

NIST is also testing more reliable elevator-dedicated盡心盡力的，盡職盡責的, 專用 emergency power systems and waterproof elevator components組成部分；成分；零件 to be used in the new generation of elevators.

      Besides hardware and software improvements, NIST also incorporates包含 its expertise專門技能（知識）；專長 in virtual虛擬 reality simulation類比，模仿 into the making of the new elevators. Virtual虛擬 reality simulations類比，模仿 help test scenarios設想； 場景, 計劃 for coordinating聯合, 協調；使相配合 firefighting activities, and for elevator and stairway（公共場所的）樓梯，台階 evacuation. By including elevators into its graphic清楚的, 形象的 computer models, NIST will help fire safety experts identify the most effective operational procedures程式；步驟 for specific確切的；具體 fire conditions. Furthermore此外，而且, NIST fire researchers hope to collaborate與…一起工作, 合作 on emergency elevator operations standards with colleagues from around the world. Global standardization標準化，使合乎標準 should reduce confusion困惑，糊塗；迷惑不解 during an emergency, enabling people to take evacuation actions with confidence自信；信心.