【英语时差8,16】已无危险；警报解除

During times of war or danger, nations who fear that their country could be attacked or invaded try to seal their borders against any unwanted intruders. For landlocked countries, that means heightening passport checkpoints and strengthening fences. For countries with ocean borders, it is harder. They must set up coastal¹ watchtowers and lookouts². If the coast is clear of any unwanted intruders, people feel relaxed and safe.

This phrase became popular for anyone wishing to express that they feel no external danger emerging from their surrounding environment. It can also mean that no one is watching you, or spying on you. For that reason, this idiom is also popular among the military or even among criminals who are trying to sneak³ around without police seeing them.

1 coastal   

adj.海岸的，沿海的，沿岸的

参考例句：

• The ocean waves are slowly eating away the coastal rocks.大海的波浪慢慢地侵蚀着岸边的岩石。
• This country will fortify the coastal areas.该国将加强沿海地区的防御。

2 lookouts   

n.寻找（ 某人/某物）( lookout的名词复数 )；是某人（自己）的问题；警戒；瞭望台

参考例句：

• Lookouts were spotted all along the coast. 沿海岸都布置了监视哨。 来自《现代英汉综合大词典》
• Lookouts and leadsmen in bulky life jackets stumbled and slipped after him. 监视哨和测深员穿着饱鼓鼓的救生衣，跌跌撞撞地跟在他后面。 来自辞典例句

3 sneak   

vt.潜行(隐藏,填石缝)；偷偷摸摸做；n.潜行；adj.暗中进行

参考例句：

• He raised his spear and sneak forward.他提起长矛悄悄地前进。
• I saw him sneak away from us.我看见他悄悄地从我们身边走开。