Liu Xiang is not chased after really on tortoise, this comes out through strict logistic inference.

Have a premise, the point of start of a race that yields a tortoise is in 1 meter in front of Liu Xiang.

When the gun is noisy, both runs ahead at the same time, dan Liuxiang wants to overtake a tortoise to must run first a meter this between he and tortoise distance, although Liu Xiang runs very fast, but also need proper time, assume Liu Xiang's speed is per sec. 10 meters, so, this also needs the time of 0.1 seconds, although time is very short, but climbed ahead again in the tortoise inside this period of time, the speed of hypothesis tortoise is every second 10 centimeters, so, it climbed this period of time forth again a centimeter, liu Xiang wants to overtake a tortoise, he must return this centimeter so that run, this also needs 0.001 seconds, although time is very short, but climbed a paragraph of distance ahead again in the tortoise inside this period of time... such-and-such, as long as the tortoise still is climbing forth, liu Xiang also cannot catch up with a tortoise always.

More than tortoise, other even slower than the tortoise animal, want start of a race to be before Liu Xiang only, liu Xiang is not chased after on oh.

Be blind Kan of course, but see guest friend, did you see among them body?