The Darkest Island

In a city, there are lights from cars and lamps all around. Many houses have lights on, and some businesses keep their lights on all night for safety reasons. By keeping lights on, people can see the roads well and feel relieved at night.

However, others find it ( 18 ). When the night is too bright, the light can disturb people’s sleep. Additionally, the lives of animals are often in danger.

Nowadays, such problems are caused by what is called “light pollution,” and it poses a challenge for almost every city in the world.

The people living in Sark, a small island near southern England, have done a lot to deal with this problem. They wanted to prevent their community from being bright with lights. Therefore, people cannot ( 19 ) on the streets of Sark.

With no cars, there is no need to place streetlights for safe driving. Walking and riding horses and bicycles are allowed when going somewhere. They buy lights when they really need them. However, they make sure to point lights to the ground.

On the island known for its amazingly dark skies, people can see beautiful stars. This has attracted many people from all over the world. The number of people who visit the island is increasing. Surprisingly, as many as 60,000 tourists come to the island every year. ( 20 ), the island’s population is getting smaller. The authority began to look for 500 new residents. They will probably face a new problem when new people arrive on this dark sky island.

However, others find it (18).
「しかし、他の人々はそれを（18）だと感じる。」

直後の文で、夜間の明かりによって人々の睡眠が妨げられたり、動物が危険にさらされることが指摘されています。このことから、「明るすぎるとリラックスできない（くつろぐことが難しい）」というニュアンスが最も自然です。

• difficult to relax「くつろぐのが難しい」(〇適切)
• fun to see the lights「明かりを見るのが楽しい」(✕逆の意味)
• easy to watch the stars「星を見るのが簡単だ」(✕夜が明るいと星が見えにくい)
• hard to open their shops「店を開くのが難しい」(✕本文にはない内容)