车辆在道路上行驶时，要求道路及道路两旁提供一定的视距空间以保证行车安全，称为视距限界。限界分类中不包括（）
A.停车视距限界
B.平面弯道视距限界
C.纵向视距限界
D.交叉口视距限界
参考答案：A
解析：车辆在道路上行驶时，要求道路及道路两旁提供一定的视距空间以保证行车安全，称为视距限界。主要有以下三种：（1）平面弯道视距限界。车辆在平曲线路段上行驶时，曲线内侧的边坡、建筑物、树木或其他障碍物可能会遮挡驾驶人员的视线，影响行车安全。（2）纵向视距限界。车辆翻越坡顶时，与对面驶来的车辆应保证必要的安全视距，约等于两车的停车视距之和。（3）交叉口视距限界。为了保证交叉口上的行车安全，需要让驾驶员在进入交叉口前的一段距离内，看清驶来交会的车辆，以便能及时采取措施，避免两车交会时发生碰撞。
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| The three youths leaned over the metal rails along the sea-wall and watched a few fishermen pull in their nets. About thirty metres away, a boat pulled alongside the slippery steps leading ___1__ to the sea. "Hey, look!" exclaimed Rahim. "Those two men are ___2__ heavy rocks. I thought we no longer do muscle labour in this technological ___3__. " "You don't __4___ a crane (起重机) to unload less than a dozen rocks, do you?" smiled Joshua. "But those men don't __5___ to have muscles at all,"said Michael, rather surprised. Joshua smiled. "They are ___6__ laborers who know how to spread the weight of the rocks they ___7__. See how the man positions the rock just at the slope of his 8 . Some of the rock's weight is set ___9__ his head, some on the right hand and some on the left hand. His body isn't bent. His legs are well __10___ ." "You're right, Josh. He may have a small build. ___11__ he certainly well knows his job. Dear me! And to think we have been studying ___12__! " Rahim thought about all that was happening. Suddenly, he said, "Technology won't ___13__ the human being completely, it appears." "I don't think it will. " ___14__ Joshua. "You can harvest a crop of potatoes or wheat with one of those large, multi-purpose tractors, but you __15___ use that equipment to harvest tea leaves and tomatoes, will you?""You can get a computer to __16___ multiple-choice assessments, but you cannot get the computer to produce of assess essays, can you?"asked Michael. "Well, the washing machine leaves my shirt collar quite as ___17__ as ever — that's domestic technology for you! " said Rahim. "One day, perhaps, there won't be anybody ___18___ who can carry a large rock the way those men do. It's not going to be a very ___19___ world, I'm afraid." Sighed Michael. "You're too much of a pessimist (悲观主义者), Mike." Said Joshua. " __20___ will always be other things that will make the world exciting. " | ||||
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