工人们用大型水泥块作为路障来封锁道路。

Workers used large concrete blocks as ___blockers to seal off the road.

交通拥堵成了我们准时到达的最大障碍。

The traffic jam was the main ___blocker to our arriving on time.

这种防晒霜含有紫外线阻断剂，能有效防止皮肤晒伤。

This sunscreen contains UV ___blockers to effectively prevent sunburn.