People are often killed while c____  the road. Most of them are old people and c____ . Old people are often killed because they are careless. People should look and listen b____  they cross the road. A car, a truck or a bus can't stop very q____ if it is going very fast. It will travel many meters before it s____ . Pedestrian(行人)don't know this. They think that a car can stop right away. It is h____ for a pedestrian to know how fast a car is traveling. The only s____ way to cross the road is to look at b____ ways, right and left. The correct way to cross the road is t____  walk quickly when the traffic l____ turn green.

“实践、认识、再实践、再认识，这种形式，循环往复以至无穷，而实践和认识之每一循环的内容，都比较地进到了高一级的程度。”这是人类认识发展的总规律。上述论断主要说明（  ）

下列各句中，没有语病的一句是 （      ）