55.There is supposed to be a safety ______ which makes it impossible for trains to collide.A) applianceB) accessory C) machine D) mechanism记得以前在哪看的选b,可刚刚看到是A 正确答案是什么?为什么?

55.There is supposed to be a safety ______ which makes it impossible for trains to collide.A) applianceB) accessory C) machine D) mechanism记得以前在哪看的选b,可刚刚看到是A 正确答案是什么?为什么?
55.There is supposed to be a safety ______ which makes it impossible for trains to collide.
A) appliance
B) accessory
C) machine
D) mechanism
记得以前在哪看的选b,可刚刚看到是A 正确答案是什么?为什么?

55.There is supposed to be a safety ______ which makes it impossible for trains to collide.A) applianceB) accessory C) machine D) mechanism记得以前在哪看的选b,可刚刚看到是A 正确答案是什么?为什么?
appliance的英文释义是“a device,machine or piece of equipment,esp.an electrical one that is used in the house such as a cooker,fire,washing machine,etc”强调的是具体的“设施,器械”,而machinery是对机械的泛称.此句中出现了对appliance的修饰语,已经说明了句子指的是具体事物.另外,“安全设施”如果用“safety mechanism”就太狭隘了,“设施”并非单指机械.
Hope these can help you.