50 Airline: Newly developed collision-avoidance systems, although not fully tested to discover potential malfunctions, must be installed immediately in passenger planes. Their mechanical warnings enable pilots to avoid crashes. Pilots: Pilots will not fly in planes with collision-avoidance systems that are not fully tested. Malfunctioning systems could mislead pilots, causing crashes. The pilots’ objection is most strengthened if which of the following is true? (A) It is always possible for mechanical devices to malfunction. (B) Jet engines, although not fully tested when first put into use, have achieved exemplary performance and safety records. (C) Although collision-avoidance systems will enable pilots to avoid some crashes, the likely malfunctions of the not-fully-tested systems will cause even more crashes. (D) Many airline collisions are caused in part by the exhaustion of overworked pilots. C (E) Collision-avoidance systems, at this stage of development, appear to have worked better in passenger planes than in cargo planes during experimental flights made over a six-month period. 答案c 没问题 若把答案 A 改成 这个
(A) It is always possible for mechanical devices that are not fully texted to malfunction. 问 是不是 也可做 答案 如果不是，为什么 ？？ possible 看起来好不爽~ | 
