It moves forwards when the vehicle is parked, so that it tip ons on to a pair of "landing wheels" at the front.
当车子停下时它朝前移动，结果倾置在车子前部的一对“着地轮”上。A timer task is used to periodically poll messages. php to see when new chat items arrive.
定时器任务用于周期性地轮询messages.php，看何时来了新的聊天项目。Comparison of slide of iron wheel and rubber wheel shows that slide of rubber ground wheel is less than that of the latter.
同时，通过实验研究，比较了橡胶地轮和铁地轮的滑移率，分析结果表明，橡胶轮的滑移率较小。However, the client must implement a facility with which it can periodically poll for the response from the service provider.
但是，客户机必须实现一个工具，使用这个工具，它可以周期性地轮询来自服务提供者的响应。Rather than repeatedly polling the server , the event system notifies interested parties as information becomes available .
不用反复地轮询服务器，事件系统会在信息可用时通知有关各方。Call blocking when no data was available, the call seemed instead to be polling continuously.
调用不是在没有数据可用时阻塞，而是似乎在不断地轮询。The result analyzing the data between former seeder and control system proved the system's quality.
分析地轮传动和采用控制系统的两组试验数据验证了此系统的效果。With the increase of vertical load and height of ground wheel, ground wheel slide can be reduced.
随着地轮垂直载荷的增加、抓地板高度的加大，地轮滑移率的均值、方差都减少。In order to know this, the CPU must be continually 'polling' the interface (reading the status register), and finally latched the data.
为了得知外设是否就绪，CPU必须不停地轮询接口（读状态寄存器）并最终锁存数据。