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。

youdao

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。

youdao

You don't consciously decide to stop at a red light or steer around an obstacle in the road.

Pouget 说：“你并不是有意识的在红灯时停车，或者驾车绕过路上的障碍。

youdao

He pointed out an incident when Junior deftly pulled in front of a line of a row of obstacle cars waiting at a stop light.

FORBES: Viva La Robotic Revolution!

Perhaps a bigger obstacle is French composers' reputation for writing music that is too thin, too light and too much in the head: all tweeter, so to speak, and no woofer.

ECONOMIST: The London Proms