That beams of light cannot be held stationary, and thus used as a form of memory store, is a big obstacle to doing this.
光束无法被固定在一点上被捕捉，这样只可以被用作为一种存储形式，而这也是很大的一个障碍。
2
If the system detects an obstacle that is likely to cause a crash, it warns the driver via an alarm, a flashing light, and then a tactile or "haptic" warning which tightens the driver's seatbelt.
如果该系统监测到前面有可能引发碰撞的障碍物，它就会通过警报器、闪烁灯以及可感触的(tactile or haptic)的警告——收紧驾驶员的安全带——向驾驶员发出警告。
3
You don't consciously decide to stop at a red light or steer around an obstacle in the road.