摩托车队的两名开路先锋先行出发，为重要人物的车队扫清道路。

Two ___outriders on motorcycles went ahead to clear the way for the VIP's convoy.

这些早期的实验就像是新技术的前哨，预示着未来的发展。

These early experiments acted as ___outriders for the coming technological advancements.