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.

Therefore, people cannot (19) on the streets of Sark.

「そのため、人々はサーク島の通りで（19）ことができない。」

その後の文で、「車がないために街灯を設置する必要がない」とあるので、「車を運転できない」ことが明らかです。

• drive cars「車を運転する」(〇適切)
• plant trees「木を植える」(✕本文に関係がない)
• go shopping「買い物に行く」(✕特に禁止される理由がない)
• walk alone「一人で歩く」(✕徒歩は許可されているので誤り)